600 - 485 = 115 hours.
October to January is at least three months or up to five. We will say four just for the average.
115 hours / four months = 28.75 hours. This is the number of hours per month you are short on your training time. You might have been on track to have this accomplished, yet, with the holidays in November and December, you may have missed a some time and not hit any extra time. This is a logical assumption for those who keep track of minimum time in hours.
There also could a variable number of other reasons. As you said you have a 91 on the written, I assume you saw the paperwork and that a 91 was at least above a minimum requirement to proceed. Noyou sau you ave the minimum physical requirements. Are these push-ups and sit-ups and running etc., ..., . Or are they actual techniques? If they are just cardio, and you have performed them, and can perform them at will then good. If they are techniques, then who said you passed that section? Was it one of the junior instructors? or the head instructor that makes the final decisions on who is presented for promotion?
Keep this in mind I do not know you, nor an I am saying this is you. I only bring it up so you may reflect up it yourself. No name calling or insults implied.
There is also an issue with attitude. Has your atttitude changed? Has it not increased? No one can truely answer these but you.
As to the check issue, the instructors could be eating and paying bills from the dues and testing fees they collect. If this is the case then having students prepared, ahead of time wiht a check guarentees that that the money will be there for them. As to holding the check, that all depends upon the person putting into the computer. If ti is submitted with a bunch of cash and other checks and a deposit slip, most likely the date is not being reviewed and the person entering the data has entered the current date as the transaction date for the electronic filling. Date a check for the exact day it is due to a company and then send it to them early enough for them to get it and have to hold it. They will process it. Many times electronically and your bank will pay them early or before the date on the check. So, it depends on the human when it is deposited.
Now if the instructors made a mistake, about your hours, and your skillis fine and proper, I personally might wave it if all other things lined up including attitude. Yet, this is me and not your instructors. They also may have confused you wiht someone else for the amount of hours and if this is the case they should admit it and apologize, in my mind.
Not sure if this helps