25% owner and nonallocation period

[Guest dlm]

Background.

Owner A and his sons in aggregate owned >25% of nonpublic traded stock. Owner did 1042 for a portion of his shares. This was a transaction with multiple owners selling shares so that ESOP owned >30% after transaction. Transaction #1.

5 years later owner A sold additional portion of his shares and exercised 1042. At this time he did not own >25% in aggregate with his sons. Transaction #2.

2 years later owners B &C sold to ESOP in transaction #3. Both excercised 1042. Transaction #3.

Question:

Does the indefinate nonallocation period for 1042 >25% owner apply to any transaction or just the first transaction that occured when owner A and sons in aggregate owned >25%?

And if it only applies to number 1 transaction then it appears that owner A sons can get allocation of transaction #2 after 10 year nonalloc period and can get allocation of transaction #3 from the get go.

The code/regs on 25% owner and articles i've read never seem to have multiple transaction examples. Can anyone point me to a good reference source?

Thanks.