v22 mod is working now!
Thank you for your help and support on this Xposed mod, I spoofed the version manually to 126.96.36.199733 (latest as of this post)
I was using Mr_Its v19 before and it was working so-so (not Mr_Its' fault - it's the Skype build that was shotty on my SGS5) sometimes the speakerphone wouldnt work correctly, along with calling/receiving calls not working (pressing the green button did nothing - and sometimes it would answer the call but the other person couldnt hear me)
I think ill get better luck with v22 and this Xposed mod! I will post my findings after some testing