Hi Vamitul,
Don't mind one bit!
Notice that I took the out the line
app.findGrepPreferences.findWhat = ".+";
because it's not needed.
I have also found that using fastEntireScript undo mode can be very risky when changing grep preferences and it is better to forgo on the speed and use entireScript undo mode.
besides that the script are quite similar 
doc verses myDoc / for verses while