Thats is definitely the way to do it!!
Get the entire set of paints at the start.
Not only do you save a little on the overall price (looks like about 20%)
but you are going to save on future shipping costs, and/or trips to the hobby store.
Plus the time spent/wasted/waiting on future orders.
It all adds up, doesn't it.
I'm impressed.
I almost wish I built enough plastic models to justify buying a set of paints!
(I've only built two plastic kits in 30 years)
FYI in Canada, the full set of Tamiya paints is 106 paints. I wonder what the extra two are?