First I think you need to clarify what you were awarded. You said you were rated at 40% permanency. Were you receiving benefits every week when starting when you were first injured? If so, that is ttd (temporary total disability). The award you just got is PPD (permanent partial disability) which is the value that the percentage of your disability that is permanent. You are only partially disabled at this point, unless you have doctors that have said you can not work at all any where. I've spent over 10 years working in a law office only handling workers comp claims and although down the road if you injury gets worse you could always go back to court and try to get permanent total. I can tell that permanent total is very difficult to get and there are many factors. I just got 60% for my back which is Serious Disability but no Permanent Disability and I got SSDI. As for your current award and your concerns about it discontinue it won't as it isn't TTD and the order specifies how much and for how long period. But it does end after the 24 months.
A neck injury just like a back injury is serious, especially if you have had surgery so think before you jump into a settlement. Yes, you might get a nice big check alright but what are you going to do as you get older and say in 5 or 10 years you need surgery, whose going to pay for it? I'll tell you who, you are. SS will not cover it as it is work related and w/c won't because by settling your case you closed it. Follow your attorneys advice. Even with all my experience I could have handled my case alone, but I'm not that stupid and I have followed everything my lawyer said. Think beyond just the money you have to think about your health too. And if your doctors say you can't work, then by all means file for SSDI. I wish you well.