I would say that at 25% BF, and 235, you should be getting about 3150 maintenance without any exercise and moderate daily activity and assuming that by "student" in your profile you are under 30.
At 25% I would aim for a 1000 cal daily defecit, or a little more.
An hour of nice and slow cardio is only going to burn 450-600 cals. Stairclimbers and treadmills on an incline tend to jack up the calories, and actually avoid muscle loss because there is less eccentric stress on an incline.
My feeling is that an hour of cardio 4-5 times a week is too much. 4-5 times is fine but an hour is inefficient.
OK, that's a lot. ARe you pushing up the incline on the treadmill? If you can jack the treadmill up to 12% at around 3.0 MPH you should be burning around 1000 cal/hour and at that pace will have some after effect as well. I would start at that level if you can for 20-30 minutes 4-5 times/week. Gradually raise the MPH. If you are already working at that level, you are doing way to much right now. Strive to increase the MPH even if you have to use intervals-say 2 minutes at 3.6 and 12% and 1 minute at 2.0 and 6%.
Anyway, 25 minutes at a high intensity will give you around 2000 cal defecit a week. That would mean that you still want to average 2400-2450 cals a day minimum. Whatever you lose above that is surely muscle in my opinion.
I would vary this over a 3 day period to total 7500, but you can go medium on one day (2450) higher the next (3000) and then lower on the third day (1900).
Are you sure about your calorie count?
If you are doing the treadmill on a high incline now, you may have picked up a couple of pounds of muscle in your hamstrings and calves.
Anyway, if you find something useful here, good, but look for your own answers.