Simply press MORE at the homescreen, and then press a number, and that is set as the new precision value. It is very large. Its large size makes it nearly impossible to edit because of the ten minute plus compile time, and you spend nearly that amount of time just scrolling through the program listing to find the right place. It was last updated in 1998 before I knew assembly. ElemNtz covers elements 1-109, with complete data on state, type, and atomic numbers and weights.
Some elements have oxidation state and common isotope information filled in too.
A find feature allows you to search the ElemNtz database if you know the atomic number you are looking for.