No, that's not what was said. If you are selling two rifles, for example, putting two descriptions in the title is perfectly proper. I said don't put variable info in the titles. As an example, if you don't plan to ever change the price of an item, then putting the sale price in the title is fine, but if you do, please don't ask a moderator to edit the title to reflect the price change.
This isn't the only board that doesn't allow editing after a few days (4 days in our case). That is true on many boards. If it was possible we would like to give the buy/sell forums a little more edit time, but it isn't possible to change that parameter on a forum by forum basis. Four days was chosen for the main forums so that posts couldn't be changed weeks later and completely alter the flow of the ongoing conversation. So it won't be lengthened to accommodate the b/s/t forums.
In fact, we are one of the few boards that allows the OP to lock their own threads. After an item is sold, we encourage the OP to lock their thread to indicate that it is no longer available. You can lock a thread at any time - even years later.