After visiting TST's website I had to rewrite my response.
*[did you mean Live trading?]
You are mixing up Live trading and Combines. In the Combines there are no differences, one is the exact 1.5 multiple of the other in every category.
Now in Live trading it is possible that the guy finishing the 150K Combine gets the 4.5K max. DD, compared to the 3K max. DD of the 100K Combiner. Doesn't really makes sense since both start out with 3 contracts max. and the former trader is supposed to be better, so why would they allow him to lose more?
But that is what their website says, so I guess, the extra 50 bucks in fees buys more max. DD in the Live account. Also there is a slight difference in the scaling up plan.
Yes as per my post I am talking about the funded trader (that you term live trading) difference between the $100k and $150k combines. The former has 3k draw max, the latter $4.5k. Thats the difference. TST could potentially lose $4.5k if you blow out on funded $150k combine compared to $3k loss to someone blowing out on funded $100k combine. The combine cost is higher as the risk to them is higher.