I realize rate of sale can not be sourced, and I also understand why the TSM team will not do that under present circumstances.

My vague response was more leaning towards the fact that you can, in a manner of speaking by using a check and “Max Expires”. Say you want 30 max expires of an item before it stops posting, but want to make sure you're not spending more on the item than what your AH fee will be over it's lifetime. You make a custom price (to keep it clean) of:

30 * (60% VendorSell) - This would be for 30 total 48hr postings, let's name it "LongAuction"

For your shopping string, you could use:

Check ({your minimum price in the auction operation} - LongAuction, {your normal shopping operation - LongAuction to account for worst-case expiry loss})

To play this out, if the item’s vendor sell is 25g, then the fee is 12.5g. 30 expires multiplied by 12.5g fee is 375g. If your minimum sell price of the item comes out to 350g, it will price the item above 100% of your shopping operation. If the minimum sell price of the item is 400g, it will be within your normal shopping operation values.

So, it could look something like this:

check(DBHistorical-LongAuction, 30%(DBHistorical-LongAuction))

With this, you can accomplish pretty much the same thing by accounting for an automated expiry limit, rather than by trying to gauge each item individually. Is it foolproof? No, but it's the closest thing to what you're describing while still trying to keep the processes more automated.

Obviously, the more expires you allow for, the fewer deals you will find without narrowing your margin for profit. Once the item reaches the limit of max expires, it's up to you to figure out what you want to do with it.

Sorry for the late response, I was just replying in theory and I wanted to test to make sure I wasn't talking out of my ass. I just ran this with multiple groups, works how I thought it would.

I'm sure the formula could be improved upon, but that should give you the basic idea.