It just doesn't make sense to me. I make my own lock parts and yes, keeping all the parts for five different locks in inventory is a head ache but...
When I run waxes and send them to the foundry they don't care about the PART, they care about the alloy only. I must supply a minimum of course but if the order is for 8620 then I can mix and match any parts that are cast of that alloy. Bridles, cocks, lock plates etc., they don't care. So if TRS needs one bridle to fill your order they don't need "three other people" to order the same part, they can throw it in with any order for the same alloy. This is assuming that they are lost wax molds. Most of them are.
I've had issues with them before, heard the excuses, they don't know who they are talking to and I can smell :bull: a mile away.