Thanks!

78th meaning MacKenzie tartan?

I notice in the 1819 KPB 78th tartan is listed, down from the three regiments which were wearing MacKenzie prior to 1809, the 71st, 72nd, and 78th. Sadly the 71st and 72nd were de-Highland-ised in 1809.

Oddly the 72nd, when re-Highland-ised in 1823, adopted PCES tartan instead of MacKenzie. Why was that?