Adjusting lathe post for interpolation error?

[gandp]

I know this is a machine side parameter issue but I don't know if it's possible to set arc interpolation error in my old Fanuc 5T machine. Can I change the post somehow? When cnc data is entered into memory the control automatically rounds up a odd 4 place decimal to the next highest even number. Example....X4.1121 in the code reads X4.1122 in the control. Now when I do complex arcs posted with odd X data the control will sometimes error if the data in the I & K vectors round up or down the same way. Normally I deal with this by carefully removing the I & K's in the rough code and change the G02's, G03's to G01's but on the finish cut I have to take the time to quess which way is right. Or sometimes it works when I regen the toolpath when I change the toolnose radius slightly. Well, this time I scraped a valuable part all do to this stupid control because I got in a hurry and made a program mistake. (I wish it would of errored here then!!!!!!!!!!) How can I adjust, either mathematically without guessing if I get alarms on arc errors? Can I edit the post somehow?

[gandp]

So basically my question is...........Is there any way I can edit my post so it outputs even X & I values? If not, is there a way to output to 3 place decimals instead of 4.? Im sure there is so that's why I ask. Thanks