[2021] Honor cost : Beta vs Live ; an increase of 35%

That is correct, except it’s a 20% reduction from Season 1 to Season 2, and then another 20% from Season 2 to Season 3.

An example:
Sergeant’s Cloak Season 1 cost: 11794 Honor (+20 AB Marks)
Sergeant’s Cloak Season 2 cost: 9435 Honor (+20 AB Marks)
Sergeant’s Cloak Season 3 cost: 7548 Honor (+20 AB Marks)

That is certainly the case for me and my memories. I didn’t personally spend any Honor in original TBC until at least patch 2.3, because my raid gear was fulsome for my PvP purposes the first year of TBC.