Pretty much spot on. "5% for 100g" is a bit bit confusing. 5% = 5g per 100g.
The reason 5% is OK for yoghurt is that it contains 4.7% lactose-based sugar which metabolizes as glucose and so is OK. But beware "low fat' yoghurts . . when they remove the fat the flavour goes with it and is replaced with sugar and salt.
Do keep posting your progress :-0
JohnN