Lil-rob,
First let me say I understand what you are going through physically. It's not easy and people in our lives don't understand just how much it hurts. I have had two fusions. L5s1. The first failed and they had to completely remove the first one in order to re-fuse the joint. In the past year we discovered the hardware screws were actually bending inside the joint. This on top of all the other secondary pain issues and muscle problems.
So, after the second fusion I wasn't given an increase at all because of the incapacitating episodes. The ROM at that time was the same. Now that the hardware is failing I had a new c&p and it appears everything riding the ROM and the incapacitating episodes, which have become more than six weeks in a year. My only advice is, make sure you are completely honest with yourself regarding your rom,what I mean is, you know when it hurts and at what point it begins to hurt. No need to impress anyone or feel like you have to give it everything you got. I found that an examiner was willing to let me push myself to a point I lost feeling in my legs. They simply tell you, go until it hurts. You already know what that means. They won't make you go further, they're just waiting for you to say it hurts at this point. Let the cards fall after that. As you know, the levels above your fusion begin to fail over time. This is happening to me yet there can be no ankylosis yet. You will probably need to take a second look at all of the secondary problems with respect to your increase...radiculopathy,muscle damage,sciatica,etc.
sorry to carry on but like I said I understand...........the short answer...definitely get a FDC going! Even though mine is six months waiting...worth the wait