GRIDPOINT may round large numbers. For example, a value of 18,000,001 in a grid may become 18,000,000 in a coverage.
This document shows how to reapply the values before they were rounded from an integer grid.
This is a known issue with GRIDPOINT.
Tables: ADDITEM mygrid.vat newval 6 6 i
Tables: SELECT mygrid.vat
Tables: CALCULATE newval = $recno
Arc: GRIDPOINT mygrid mypoint newval
Arc: JOINITEM mypoint.pat mygrid.vat mypoint.pat newval