What is this modified version of Hanyu Pinyin called?
Isn't this just an informal romanisation method to make it easier for Malay/Indonesian speakers? 

In those languages:


c is pronounced /c/, so it can be used to approximate z/zh
k/t/p are unaspirated, so h needs to be added to indicate aspiration
au is /aw/, same as mandarin ao
There isn't /ɨ/ as in Mandarin but /ə/ which sounds close to it, and /ə/ is written e.


This is probably just the work of one person transcribing the music for an Indonesian audience. Pinyin has some weird spelling conventions so these adjustments help Indonesian speakers sing Mandarin songs better.

You can see this a lot with Cantonese/Hokkien songs. Mandarin is much much better in this regard.