update record sheet from production sheet

dear friends here i have attached my document.in my document first sheet I'm keeping record about my daily production.second sheet is my production report.what i want to do is production report data should copy to first sheet correct place,for that second sheet column "B" first 6 characters need to mach with sheet one column "M".if it is matched then sheet two same row column "G" values should copy to first sheet column "N".if at that time any values are already there then don't overwrite that values & new values should combined.
ex-
old value = 5
new value = 10
after running macro =5+10
pla any body can make macro for this.it's very big help for me.thanks.