Divorce Support Forums: modification of child support

i have a modification hearing coming up on monday and was looking for some input or what to expect as i am not taking my attorney for this one. so here's the story: original child support ordered in march 07. in june 08 sons dad was in a bad accident rendering him unable to work and motion to modify was filed. he is currently getting disability from his work from which the child support payments are being taken out of. his disability will run out in november. he has filed for social security/ he does not know yet if he was approved, but was told that if he did get approved that it would begin in december, and that my son would get his disability amount. so i am thinking that we will go in to the hearing and they will calculate from what his income is now(disability from work). am i correct? my income has stayed almost the same in the past year, and his went up alot .....until the accident..../ would this make any difference? or do they just look at what his income is right now? i am just a little nervous and need some input on what to expect. thanks