The manual says the voltages should be within 15% of what is listed on the page. To calculate a percentage, subtract the difference between the voltage you are seeing and the one listed in the manual. For example your first voltage is 98, so it is 8 volts higher than the 75-90 rage listed in the manual.
Now divide that difference by the number listed in the manual. We have a range of 75-90 in this case, but just use the top of the range for this case, 90 volts. 8/90=.088. Multiply that answer by 100 to get a percentage, 8.8%.
8.8% is less then 15%, so that voltage variation is well within range. You can do this for each measurement. With some practice you can do this math in your head pretty easily.
