Q. Our shul does not have the custom of everyone having an Aliyah on Simchas Torah. Our minhag also requires only having 6 Aliyos from the first Sefer Torah (including Chosson Torah).
This past Simchas Torah, the fellow who bid for the 5th Aliyah turned out to be the son the the one who bid for the 4th Aliyah. After the 4th Aliyah, the Gabbai was unsure what to do. On the one hand, he could ask the winning bidder for the 5th Aliyah to honour someone else with the Aliyah. However, he bid for it thinking he would get the Aliyah. The other idea was for the schul to seek bids for the new 5th Aliyah which would consist of 3 pesukim of the beginning of the Aliyah, and then call the son for a reduced size Aliyah that would be a Hosafah before Chosson Torah. However, maybe he didn’t bid for that either because he bid for one of the mandatory 5 aliyos, not for a Hosafah.
What would Rav Miller have ruled?

A. Horav Shlomo Miller’s Shlit’a opinion is indeed to make a hosafah before Chosson Torah. The bidder for the fifth aliya, was at least partially responsible to have been aware or asked who bought the fourth, and should therefore settle with a somewhat diminished aliya.
The Rov mentioned that in Lakewood Yeshiva, although they did not normally call hosafos, when there was a simcha and the aliya required was for a Cohen, they did add a needed achron.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a