With many more to come it looks like:

Per Austin Energy’s policy, it can only adjust the PSA in increments of up to 5%.

Paraphrased "We would have raise it more in one go, but we're not legally allowed to"

“The increase is required to continue making progress on recovering power supply costs in order to position Austin Energy for an anticipated PSA under-recovery during the summer months,” AE said.

Paraphrased "We've got a bunch more of these 5% increases coming to you in the near future"