Also all of the items used in the video can be borrowed and the effect can also be performed 100% impromptu.
Actually, they can't and it can't. Simply put, you can't perform the effect with a pad of sticky notes, a dollar bill and calculator that you borrow from me without having done anything prior to the effect. Could you do the set-up on the fly? Maybe, but it is would be very difficult.
Now, I'm of the mindset that the words "impromptu" and "borrowed" and "can be examined" should be removed from the magic marketing vocabulary. Mainly because those terms are too often used to mislead. But also because the fact that something requires set-up or a switch or ending dirty doesn't make a difference to the spectator because they don't see any of that.
That being said, it is a good use of the principle that Rich Feurgson teaches in "This is Mentalism." Although that isn't were you learned it, I suspect your friend who taught it to you got it from there (either directly or indirectly). I like the idea of the calculated number being on the bill.
I also agree with ChrisWiehl in that the double reveal doesn't add anything to the routine. In fact, I think the double reveal makes the spectator think that what they have seen is more of a trick than magic. That is, if the number appears on the sticky note, you must have known it before the effect. It is all too perfect.
Finally, there is no real justification for why the effect happens in your presentation. Did you influence them to select certain numbers? Did they notice the numbers on the bill subliminally and just happen to type the numbers that equaled what was on the bill? Maybe you could type in the last number and attribute the effect to you ability to memorize numbers and do math (Harry Lorayne used to teach memory classes and impressed the students by forcing a card and then looking through the deck and naming the one card that was missing).