Hi.

As far as I know, the T5 Excelsior (Advanced Heavy Cruiser Retrofit) is not max level, but can be bought as soon as Rear Admiral - Lower Half (level 41), so the ability scales as you grow from RA-LH (41) to Vice Aldmiral (51), up to the maximum of +7.6 extra power, (the same way, for example, as the Standard Issue-S equipment and weapons grow for shuttlecrafts as you level up).

Cannot confirm this, though, as I'm already VA and still planning the purchase.

Regards

L