Have you had a study with CPAP to make sure it works? It's be nice to be sure the treatment is effective before committing to it. Aside from that I'd strongly consider buying my own machine if I were you. You will save a lot of money. Especially when you have support of a helpful doc.
One problem with home based studies is that they often have very few sensors. It is possible to get one (such as the one I use) which has the same array of sensors as an in-lab study, but almost all of them have far less. This is generally for 2 reasons. 1) this makes the equipment much cheaper to buy and easier to use. 2) The fewer sensors, the greater the chance of a false positive and therefore the more chance of selling a CPAP machine. There was a big fuss a few years ago when it was revealed that a lot of home studies were being performed, and treatment sold to patients, without a doctor being involved at any stage.
Home studies absolutely have their place in the landscape of management of sleep disorders but, as with all things, they need to be used intelligently, responsibly, and with a focus on good patient outcomes rather than making money.
A CPAP machine, no matter how smart, cannot rival a monitored sleep study in terms of the level of data it returns. A CPAP has 1 sensor to generate all that information. This is one reason why data from a PAP machine has to be taken with a grain of salt. As an example, the sleep study I am recording right now has 21 different channels of data. This is one of the reasons why a proper BiPAP titration can only be done in a lab because there is no other way to get all of the required data (CO2 levels for example).
As with all things medical, there is no substitute for trustworthy, reliable medical advice. A good doctor will work with you and educate you to achieve the best outcomes. A not-so-good doctor will glance at the results, rubber stamp your treatment (or other course of action) and barely acknowledge your presence.
It's worth bearing in mind that, as long as you are in the process of pursuing treatment that your licence shouldn't be in jeopardy. In almost every case I've heard of, people only lose their licence if the flat out refuse to be treated. If you do as the doctor suggests, even if it takes a long time, you should be OK because you are doing all that you can. Of course, there are no guarantees.
The rules in Australia vary from state to state, but if you hold a Pension Card or a Health Care Card you can often access treatment for free (or close to) depending on the severity of your OSA. The private sector often takes advantage of OSA sufferers in various ways, with unnecessary tests, overpriced equipment and so on. One extra problem which we have in Australia is that auto CPAPs cost AU$1000 - AU$2000 more than fixed pressure machines, which is not the case in the US. It is often possible to order a machine online for much less than you would pay for one in a shop. Most patients are, not unreasonably, reliant on their doctors and other medical professionals to give them sound advice which is in their best interests. Unfortunately, too many medical professionals are lured by the easy money which treating OSA can offer.
What you describe is a genuine problem. The law in Australia is that a doctor is required to report a patient to the motor vehicles department if they think
the patient's ability to drive is impaired. Some research has been done into the matter and it suggests quite clearly that more people would be treated, and thus we would all be safer, if reporting of patients was not mandatory. What happens to your licence is largely up to the doctor involved with your case. Most of them are sensible and generous in how they apply the law, but you never know. I have also heard from a lot of my patients that in the last year the authorities responsible have become much stricter in chasing up people with OSA.
Sleep apnoea can occur at any age, right down to neonates, so you could have had sleep apnoea from childhood. The deviated septum is essentially unrelated.
With that little equipment the result is not terribly reliable. I'm glad you have an in-lab study booked. With just those 2 sensors, they would not have been able to tell when you were asleep, leave alone which stage of sleep you were in. They can't report a real AHI because those 2 sensors don't return the data required to determine an apnoea or hypopnoea according to the rules. Some brain activity data at least is also required. In fact, that is the most cut down set of sleep study gear I've ever heard of. It sounds rather suspicious that after performing such a flimsy test they were so quick to offer you to spend money on treatment. You may well have OSA, but it would be worth waiting on the lab study to get a clearer picture.
An AHI of 29 is not good, although it could be a lot worse. It's certainly of a level that you should do something about it. Sometimes events scored as central in a sleep study will respond to CPAP for various reasons, so don;t count it out yet. The best practice approach is a study in a lab where they can start with CPAP and see if it works, and If not they can swap to BiPAP (which is the standard treatment for centrals apnoeas). ASV may be required but it is only used in very specific circumstances and should always be done through a sleep lab and in consultation with a doctor because ASV can be risky if not used appropriately. Overall, don't get too worked up. In all likelihood you can be treated. Also, remember that the damage done by sleep apnoea is done gradually over years, not all in one moment, so it is important that it be treated but it doesn't all need to be done tomorrow.
Why do you have a BiPAP and and not a CPAP? At an IPAP of 8 and an EPAP of 4 it's doing almost nothing that a CPAP of 4 wouldn't do, apart from slightly increase your chance of leaks.