How do I get my Wanhao Duplicator 6 / Maker Ultimate to lower bed at end of print?
In your ending script add the line below and change Z200.0 to your max Z height.  This will rapid to the given value using absolute coordinates.  I added G90 in case G91 was previously set so it did not do a relative move.  I'm not positive if G91 is modal in printer firmwares or not but the G90 should not hurt anything.

G90 G0 Z200.0