Please some help/idea on this code from MsxBr-L(tutorial);

I am learning assembler(z-80), and like some opinion about line 200 of this code, i am thinking he used this because changing/increasing hl register would make some change in flag register, i'd like some opinions about this, and other thing i saw, increasing hl on line 200, it will move all address of instructions(registers C,B,D) to more one address+("somado") (not alligned with the original position), would this cause problems this?
link to code:
http://pastebin.com/9yrYmP3G