Well, that's new and important information. Better mention that in your original post next time.
The idea behind gauges and their scales & ticks is that the scale is divided into a fixed number of zones (Properties->Presentation->Major Units - 1) and independently of the actual gauge segments, EXCEPT for the start and end values of the gauge. You cannot assign immutable label values to those ticks because they divide gauge max - gauge min / (number of major ticks - 1) to get the actual label values. If they wouldn't do that, and you expect to have labels like 20%, 20%, 60% and so on, what would the gauge scale look like when the min value = 22% and the max value is 39% and you want 6 major units? That would lead to some sort of infight between gauge range & tick mark range.
Maybe you should fix the gauge range (to 0 -> 100%) and add an actual value display in the lower center of your gauge. The latter is meant to display large values when the needle gets stuck at the upper gauge limit (=100% and no further). You can add an expression in Properties->Presentation->Text in Chart to do that.
