AC main power to high.

I just built a Tubelab SE amplifier, with 300B output tubes. It was designed to work with 3.5K output transformers, at 365 volts B+ voltage, with 120 volts AC main power.
However, my AC main power is up to 124 volts AC in the morning. And I've seen it get as low as 120.5 volts at night. This give me a swing of about plus 15 volts on my B+ voltage.
Maybe I'm being anal, but this really bothers me. Some suggested getting a regulated UPS. Then someone else said that a ups would introduce noise into the system.
I'm looking at the Tripp lite, Smart LCD 1500, regulated UPS. It says it protects against spikes and surges, Cleans up noise, and give a regulated 120 volts AC without using its batteries.
What is your opinion? Should I be worrying about the +/- 15 volts on my B+ voltage? Will a regulated ups help or hurt things?
I wish I could afford a PS Audio Perfect Wave AC power regenerator, but that's not in the cards right now. So what do you all think? Thank you all.