Oil question about an H6750 NH cutter

I bought this cutter new, cut about 120 acres. I changed the blades an decided to check the oil even though it wasn't at the 50hr change time.

I had to add 8oz to the Drive module(it holds 10oz), I called the dealer. He gave me a new vent plug and told me to check some of the bolts for tightness, which I did. I cut about 40 acres more and brought the cutter home and was cleaning it up to put up for the winter and power washed it and decided to change the oil in the cutter. In the same module I took out the check plug and nothing came out. I took it to he dealer. My question is should I have had to add that much oil in that little of time? the next oil change is at 200 hrs or yearly????.

Thanks

Oil question about an H6750 NH cutter