Replace Full Height Window

Was thinking about replacing the ugly dark color full height window by natural color aluminium window.. ID all the way said OK OK till today he suddently said becoz the window is full height, he need to apply for PE endorsement which costs around 500-800 and apply sth called PAC which costs 2000 bucks and not gurantee it will be approved~~~ OK.. maybe he never did house with full height window and owner wants to change it before..

anyway.. is this true that replacing the full height window need to apply for so many things? My ID told me the window frame cannot be replaced unless apply for PAC.. I can choose to only replace the casement window glass which only requires PE endorsement.. but I defintely have to put back the wrongt iron grille which is for the lower half of the window.. How about the casement window frame itself?

The current window color looks so ugly and a lot of hedges are rusty and one of the window even can't be closed completely... is there a way to change it??