How are you going to use the return values? Actually, it doesn't lose precision when you use the return value of getpoint.
Command: (rtos (car (getpoint)) 2 10) "712.3574499142"
The rtos function returns a string that is the representation of number according to the settings of mode, precision, and the system variables UNITMODE, DIMZIN, LUNITS, and
LUPREC.
Arguments
number
A number.
mode
An integer specifying the linear units mode. The mode corresponds to the values allowed for the LUNITS AutoCAD system variable. The mode can be one of the following numbers:
1 Scientific
2 Decimal
3 Engineering (feet and decimal inches)
4 Architectural (feet and fractional inches)
5 Fractional
precision
An integer specifying the precision.
The mode and precision arguments correspond to the system variables LUNITS and LUPREC. If you omit the arguments, rtos uses the current settings of LUNITS and LUPREC.
Return Values
A string. The UNITMODE system variable affects the returned string when engineering, architectural, or fractional units are selected (mode values 3, 4, or 5).