Glad you are making progress, but I don't have a lot of specific advice I can give you on the details you are wrestling with. A few cursory comments:
(1) You are correct that any loss not allowed would be carried over - each year, you just pull prior losses into the total, and deduct what you can via new stock or debt basis, and then again carry forward any excess - you never "lose" any prior loss, it just keeps rolling forward...
(2) Prior to this year's introduction of the 7203, I have never relied on Turbotax or the K-1 to carry loss information forward, I have always just handled that externally to the program, and made entries in following years accordingly.
Specifically, I have always just entered into the Turbotax K-1 the ALLOWABLE LOSS, not the loss as actually reported on the K-1 issued by a company. At this point, the 7203 has calculated the carry forward loss (because in Form 7203 lines 35 - 46 and totaled in 47 ARE THE REAL K-1 LOSS ITEMS AS REPORTED BY THE COMPANY), we'll see "next year" if this carry forward flows appropriately!
Hope you find a solution...
