So you only put it now on level 100 with 90 million hp? great one without saying it in patch note
Nothing was changed about level of CoT objects. Only thing which was changed is:
Tactic elements in Course of Terror mini game cannot be destroyed anymore by classes AOE skills
And yes, you noticed correctly by simple way - HP increasing; updated in patchnotes if it's realy big deal
I strongly suggest you to do CoT using tactic elements, if you corretly do all moves you are supposed to complete this in every combination since it is not anymore randomized, but based on predefined structs. There should not be not possible to complete versions of CoT.
You need only one Artillery Vehicle for destroy Giant's Iron Barricade.
That is how it was in the past, when noone was capable to destroy any object using skills.