Good overall, but I think the math is wrong. highest/lowest score is actually 136/-136 not 152.
Proof: 6(number)*4(Rounds)*2(possible 6's)=48 plus 5*4*1=20. 68 is the highest number for the first 4 rounds leaving 6 rounds left. at this point both 6's are done and 1 5 is done. the highest combination for the next 3 is a 5 and 2 4's. For the next 4 of the 6 rounds the highest you can get is: 5*4*1=20 plus 4*4*2=32 52 add 52 and 68 you get 120 and you have 2 rounds left. the highest number at this point is 2 3's and a 2 for 2 rounds. 3*2*2=12 and 2*2*1= 4. 120+12+4=136 maximum total if you are even that lucky.
Aside from that it was fun I got 100 one time :)