Hi @Anonymous ,
I've made a similar test in IE and not met the same problem like your description.
Here's my test:
set the label's Text:
Round((0.75 + 0.5 + 0.6)/3*100,0)
And the label display "62".
So the caoculation and Rond function in IE has no problem.
I think the problem is your column's Value.
Could you make sure that :ThisItem.Progress1,ThisItem.Progress2,ThisItem.Progress3,ThisItem.Progress4 and ThisItem.NumberOfStand display as "0.75 ,0.5 , 0.6, 3" in IE?
Since they are calculated fields and formatted to percentage, so it may has some problems in displaying.
Please check this. If they do not display as "0.75 ,0.5 , 0.6, 3", I suggest you transfer them before calculating.
I've found some has met the similar issue, he used this to transfer:
Concatenate(Text(Round(Value(ThisItem.CompletionScore)*100,0),"[$-en-US]0"),"%")
https://powerusers.microsoft.com/t5/Building-PowerApps-Formerly/Show-a-percentage-from-Sharepoint-list/td-p/96949
Best regards,