A lot of emphasis (or often times a lack of emphasis) is placed on the word “guides”. The guides, as well as electronics, need not be EXACTing. If a guide says 2.3v at a specific point, but the measurement is way off, but it still sounds as anticipated, hoped or good, then the EXACT measurement is not as important as the end result. Electronics is a fickle mistress and she can be devilishly playful. So, if it sounds like another you’ve built and\or works as expected, a pinpoint voltage measurement at a specific point is not really required. What matters is that it works.