Tiered commission plan with new accounts plan paid monthly

I posted here a few weeks ago and someone was able to help! I have an added twist to the commission plan that I got help on.

I need to have sales of new account commissioned at a different rate than the normal commission plan. However, I would also like to have the sales of the new accounts included into the overall commission cumulative sales total. In that way the salesman is able to move into the next commission tier. I do NOT want to have the sales of the new accounts to be double commissioned, ie paid at both the new accounts commission rate and the normal commission rate.

Therefore my question is: How do I get the sales of the new accounts to be included in the normal cumulative sales plan total without it getting commissioned at the normal sales plan rate.

See attached spreadsheet. I have the new sales accounts and the commission for it separated from the normal sales plan. But I don't know how to include the sales of the new accounts into the sales of the normal plan without it getting commissioned at the normal plan rate.

Help!!! thank you!!