coupon codes not correct discount

[bryanfilm]

When I go to create a new coupon code I enter 100 as the fixed amount and 299 as the minimum order. When I click insert it shows that the discount is 33.44% Which I assume is the percentage of 100 off of 299. Is it supposed to show as a percentage like that even though I want it to be a fixed amount? When I test it out by doing an order sometimes it will show -100 as the discount and -99.98 which is fine but certain products or totals will show -$84.98 or more than just a few cents less than $100. Has anyone else had unreliable results like these?

 

I would greatly appreciate any help.