Advanced Race Guide Stat Modifiers

[Kromgar]

I've been looking at the ARG to make some regional variants of some of the races for a setting I'm working on, but I'm a little confused by the wording for Advanced (Stat).
In Particular: This bonus can be taken multiple times, but each additional time it is taken, its cost increases by 1 RP. Its effects stack.

Does this mean taking Advanced (Stat) x2 cost 9( 4+(4+1)) or just 5?

Main confusion came about thanks to two of the other players who have DM'd more than me having conflicting views on it and me being unable to track down an official answer.

[Kromgar]

Also I'm setting pretty much all of these variants to 15-16 RP

[Thymus Vulgaris]

It would be 9. The idea is to "penalise" you for taking the same thing several times by making it more expensive, not make it almost free.

If the price were to be 5 for taking it a second time, then the cost wouldn't have increased by 1—it would have decreased by 3.

[PrinceDogWaterIII]

Advance (Strength) - 4 RP
Second Advanced (Strength) - 5 RP
Third Advanced (Strength) - 6 RP
Etc...

Total 15 RP

[Kromgar]

Thanks both of you. I thought that was how it worked, but as I said, couple of folks who have DM'd more muddied the waters