Any limit on columns for OFFSET

I have a large Worksheet and I am running into a problem after column ZZ (703). The line of code is =SUM(OFFSET(dataset!ZZ$8,(ROW()-3)*$B$1,COLUMN()-1,$B$1,1))/$B$1, which calculates correctly, but when I paste into columns AAA and beyond, it seems to flash a number and then become 0. The dataset page goes up to column BAZ and there is data in every row and column. cell $B$1 is a number of cells to sum together as the dataset is being reduced on the next page.

That this happens on column AAA makes me scratch my head and think I may be up against a size limitation, but I cannot find any reference to it.

I am running Excel 2013 under Windows 7. Marvin, I didn't understand your suggestion about the furthest right column and using =Column(). That would give me the numerical value of that column, not the maximum. My columns go up to BAZ, but I can add more columns. The problem is they all become zero, but only the page that does the sum on the original data. The original data is populated with numerical values that were read from an instrument file. They all look fine.

Andy, these are relative positions because I am condensing data vertically, but doing it in matching columns to the original dataset.
I wish I could attach the file but it is too large. It is 182MB, but I will try creating a smaller version but would still have at least 703 columns since that is where the failure occurs.

Thanks for the suggestions. I am still pondering this.

No limit of column.
Use counta() function with offset for dynamic range.

Thanks, Marvin for the suggestion of the Evaluate tool. That pointed out that Andy was spot on about the relative reference. I did intend it to be relative and not absolute, but I did not mean to call the column() The Evaluate worked great, showing the referenced arrays to sum.

Sorry for having to sleep on this and not respond quickly. I discovered it at the end of the day, when I expanded the worksheet to cover more data and was baffled. I stuck around for a while but maybe the sleeping on it was a better idea. Anyway, thanks and I will mark it as solved.