Okay...I have heard rumors that every 20 HM games you win, you get 1000 credits, is this true? If not, is there anything special you get from winning a lot or a certain number of times other than 5 credits per ghost and 40 for winning? Please, tell me! :)

Nope. Here's the outline-

In wins/credits
1 = 40
5 = 180
10 = 375
50 = 2,000

Still a bit confused. Does this mean if I win 5 times I get 180 credits?

Nope. Here's the outline-

In wins/credits
1 = 40
5 = 180
10 = 375
50 = 2,000
Are those just added to the regular credits u would have gotten? Or ur total amount of credits in the game?