A question came up in our local store:

Per the RRG you can have 1 unique unit for each 100 points in your army.
Do hero figure upgrades count towards this limit?

Example: In a 150 pt list, could you have both Ardus and embedded Ankaur Maro?

Since the limit applies to units, as you emphasize yourself, it is not affected by figure upgrades. They are not units after all.