@Galway1 the X in this instance I believe would be calculated thusly:
I think if you can get your average to be any amount higher than 4.950, it would (for display purposes) be rounded up to 5.
Assuming all your non-5-star ratings are 4s (heaven forbid you get any ratings below 4), then since you already have 4 ratings of 4-stars, you need 76 ratings of 5-star to get *exactly* 4.950 average.
So 77 or more 5-star ratings would round up to 5 in display.
Or, expressed another way: if you have 80 total ratings and 4 are 4-star and the rest 5-star, then your average is 4.950.
Having 81 ratings or more (all 5-star, except 4 are 4-star) will average over 4.950
Don't forget that the guests often only look at the pictures of the stars. That gets rounded up to 5 pictures of full stars for anything over 4.750, which is far easier.