"Freedom for me, rules for thee". Texas has always been a cesspit of political kickback. I mean ... not Illinois or New Jersey, but annoying enough.
From what I quickly checked you can modify your own home there is an exclusion for doing electrical work on your property - seems like main panel would be somehow excluded from what qualifies as "yours".
That exemption is from the state code and applies to "work not specifically regulated by a municipal ordinance that is performed in or on a dwelling by a person who owns and resides in the dwelling".