I think your bid is very close to what we would have bid. We add 50% for dbl cutting.
You won't have much trouble with 8" grass and you have already figured dbl cutting into your bid. You might even get away with 1 pass or just dbl cutting certain areas if you have a good mower and the grass isn't too thick.
Blade Runners, LLC
"Always do your best. What you plant now, you will harvest later."