Quoted from ccotenj:2 things that might be interesting (albeit possibly only to me)...
it would be interesting to see a measured wall voltage and a measured secondary voltage...
it would also be interesting to see wall voltage measurements at different times of the day, especially now that summer is here...
Your local house voltage can also vary depending on where you are on the local transmission lines. I live on a major trunk line. My wall voltage is always between 122-125 !