Note that to raise T6, Alchemical Laboratory >= 26 is needed.

Before first update:

Lower tier prerequisite for raising higher tiers:

First Update:

[Green 'Help' button was replaced by red 'Boost' button, below.]

- Note that there is no 'Free boost of the action in progress.' [VIP level has no impact here.]

Upon starting upgrade, Siege expense changed to 1h0m.

- as opposed to the 15m shown above. [I assume.]

After first update completed:

Note different Cost of upgrade, below.

With upgrade, Templar upgrade requirements met. It can now be upgraded - Militissa does not need to be upgraded to 2 (or 10), first.

It is not yet clear to me which is the cheapest way to upgrade all. e.g. Upgrade all level 1 troops first, then upgrade to level 2, rinse, repeat, or update a particular troop type level 1 to 10, then move to the higher tier of same troop type, or max. out the highest tier of a troop type then repeat on the next one, or ???

Thoughts welcome.

With Templar update concluded, as above, cost of Ram upgrade did not increase from the above. Nor did the Militissa upgrade (from the above).

So, it seems that the cost increase wordings relate to an increase in the upgrade costs of only the upgrade stream of another troop type.

Not an increase in the cost of any and every other upgrade, of whatever troop stream of troop type. e.g. Militissa or Templar.

[Starting Knights only increases Siege, and starting Templar increases neither Militissa nor Siege.]

Thus the given wording. So, as it says, pick your primary troop type first, then your secondary, and so on.

Which also seems to answer the question of what order to upgrade things in, for the least cost.

Thus:

is really just a reflection that this would be the nth of the 6 troop types / streams being upgraded.

I don't believe so.

Thus the many required confirmation of selections before effecting one.

They do get rather more expensive at each level.

I did troop, then Scout. Haven't even bothered trying with a 3rd.