HELP PLEASE

So after a very long and complicated process utterly confusing  day after doing keto for 2 weeks I've been informed that carb managers readings of macros are incorrect due to it being an American app that deducts the fibre and us being Australian our packets have already deducted fibres to get net carbs so carb manager is wrong and deducting fibres twice due to this reason. 

I've been noticing sooooo soooo many barcode scans with incorrect information from other people and even businesses,it doesn't make sense,I thought scanning items was a way to be absolutely sure and correct,but after checking out the nutritional information on packaging it's very different.

Is this information correct I've been told about deducting fibres twice due to different countries? 

Is this why some are scanning differently?

Also when we're cutomizing our own products entering data,do we add fibres to total carbs under carbs and fibres underneath fibres still to prevent this fibre deduction twice? 

I thought I had it all worked out until someone put a spanner in the works today.

If someone could kindly clear things up for me and a few others I'd be extremely grateful 

I was going to move over to mfp but theirs seems even more confusing than this not calculating net carbs and deducting fibres in your head not even calculating on the app so I'm told

So been trying to figure this out all day :)

Kindest regards