Automatically Updating Cover Page

[LearningByError]

Hi everyone. I have a worksheet that has multiple pages that users can input information into. The information entered is then automatically updated in a cell on the first page. I'm currently doing that for the first two sheets and it works. However, when I add the code for a third sheet I still only am able to get the values in the first two sheets. Any help is very much appreciated.

Two sheets:
=IFERROR(IFERROR(INDEX('100s'!$B$1:$B$500,SMALL(IF('100s'!$B$1:$B$500<>"",ROW('100s'!$B$1:$B$500)-ROW('100s'!$B$1)+1),ROW(1:1))),INDEX('200s'!$B$1:$B$500,SMALL(IF('200s'!$B$1:$B$500<>"",ROW('200s'!$B$1:$B$500)-ROW('200s'!$B$1)+1),ROW(1:1)-COUNTIF('100s'!$B$1:$B$500,"<>"&"")))),”)


Three sheets:
=IFERROR(IFERROR(IFERROR(INDEX('100s'!$B$1:$B$500,SMALL(IF('100s'!$B$1:$B$500<>"",ROW('100s'!$B$1:$B$500)-ROW('100s'!$B$1)+1),ROW(1:1))),INDEX('200s'!$B$1:$B$500,SMALL(IF('200s'!$B$1:$B$500<>"",ROW('200s'!$B$1:$B$500)-ROW('200s'!$B$1)+1),ROW(1:1)-COUNTIF('100s'!$B$1:$B$500,"<>"&"")))),INDEX('300s'!$B$1:$B$500,SMALL(IF('300s'!$B$1:$B$500<>"",ROW('300s'!$B$1:$B$500)-ROW('300s'!$B$1)+1),ROW(1:1))-COUNTIF('100s'!$B$1:$B$500,"<>"&"")-COUNTIF('200s'!$B$1:$B$500,"<>"&""))),"")

Thanks,
LearningByError

 

[LearningByError]

I failed to mention, the sheets names are '100s' '200s' '300s'..etc.

Also I would attach an example but I do not have permision.

Thanks again.

 

[LearningByError]

Haven't been able to fix this. Any help appreciated.