I noticed exactly the same thing, when I bet large sums whether on limbo or even dice (for example 50 dollars to 200 dollars) I systematically lose and it is only small numbers that come out..
On the other hand, when I bet small sums (0.1 to 2 dollars) the big numbers come out very often..don't tell me that it's psychological or whatever...
The numbers are there and I leave you free to think about that..I'm not in the habit of making comments but when something is true, I confirm it, with all due respect to stake..