[186 subclass] How much of a processing delay should I expect If I need to pprovide further health assessments (conducted in a different country)?

[emoelmo1408]

My 3-year-old's health clearance has been put on hold as the panel for visa medical services has requested further assessments by a developmental pediatrician. 

Due to the non-availability of appointments with a developmental pediatrician (the wait times are 1 year or longer), We have decided to go back to our home country and get the assessment there. 

Keeping in mind the delay of 2-3 months in submitting the assessment reports, how would it impact the processing time of our application?

Anyone with similar experiences? May I know how long it took to receive PR in such cases?