Prompt porting help

hey so i started porting a supernexus ROM based on 4.4.2 for my xperia u but when i open the updater script on my port rom it has

Code:
set_metadata_recursive
whereas my base rom has

Code:
set_perm_recursive
if i am to replace
Code:
set_perm_recursive
with
Code:
set_metadata_recursive
will that be a problem ? and also how do i adopt the port updater script to work with my base rom ?

thanks :
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Phone Details
[Device] : Xperia U
[Model] : ST25i Kumquat
[Status] : Rooted / Bootloader Unlocked
[Android Version] : 4.4.4
[ROM] : [4.4.4] [UNOFFICIAL] ParanoidAndroid 4.4 [RC2]
[Kernel] : [3.0.101] BraveKernel for KitKat