Water mark getting serious on my car's windscreens and windows,

Want to remove the watermark and do a coating on my all windscreens and windows, Saga FLX.
apply Pxrmanon on whole car half year before, but last for 3-4 month only (parking under hot sun)...now full with watermark...
Do I need to remove the Pxrmanon layer before apply your product? how to remove?

bro pls advice, Thanks.

And how to take care the coating?

Package below available?

2. Package 2
a) 4 packs watermark remover
b) 1 piece of 3M sponge
c) Antirain Nanotech Glass Coating 2 packs(2packs which using total for 4windscreens)
d) Shipping fee included
RM160

3. Package 3(Full coat for 1 car)
a) 4 packs watermark remover
b) 1 piece of 3M sponge
c) Antirain Nanotech Glass Coating 2 packs(2packs which using total for 4windscreens)
d) 1 bottle of Antirain Nanotech Liquid Coating
e) Shipping fee included
RM190