according to the naming regulation issued by 2012.10.1,
z for armored, L for wheeled, T for "Tuji"(assult gun type). you are right. Althought the regulation is still classified, there are some mix uses here and there in different media sources.
the problem here forZTL/ZTL is not the chassis is almost the same as zbd-08, this is because the type-11 was developed from ZBD-08 and finalized for ready to service in 2011. The main PROBLEM I recognize here is the ZTL also means amphibious tank. lol, so maybe I am wrong, ZLT-19 is fine.