Hi Friend
I can read this from calculator page :
only enter qualifying stamps e.g. Stamp 1, Stamp 4
you first six month was stamp 4 on you passport and your 5 years was stamp 4 as well and you can see on you passport it;s just written stamp 4 no temp stamp 4 .
Because it's just a stamp you are also allow to work or whatever . you need to remember that in this forum most people didn't 5.5 yeat like us. most of us them got plain 5 year as per my understanding t. it used to be 6 months then you get a card with 4.5 year more.
so there's not difference they are all stamp and should all count based on this you can apply 5-6 month before you five years expire because you would then 4.5 year + 0.5 intial
Please apply and make sure you confirm this here