Building A Squash Court

I realized that in December, the commission of my checking account was exactly 53.6% more than what I usually charge. I assumed that I had uploaded the commission, but surprise ... in January, the value returned to normal.
I call the internet support number of the bank, and the girl who answers tells me she can help me. When I tell my doubt (pq I do not know how these things work, and perhaps the recovery is good but I'd like to explain it), I said "Ah, but is that the UF was more expensive in December ...". I tell him not think he was much more expensive, but just go and look for the value of the UF on that date ($ 21,497 versus $ 21,280 this month) and calculate the value of December, according to the percentage of the UF that I charged. "Oh, that strange, does not fit ...". I tell you better talk to the executive and voice farewell with relief.
I call my number executive and - of course - I was answering another operator. I say I want to talk to my executive and I said, offended "I am also executive and I can help you!". I explain the story and guess ... "Ah, but is that the UF was more expensive in December" ... and from the calculation.
When I send the mail with an explanation (which is sure to be "Mrs. Valeria, in December, the UF was more expensive") I tell you ...