My guess is that PR wanted the capacity on the A35K to match the 77W. Apart from being able to cater to the masses.
PR's own 77Ws seat 370, while the two Garuda planes seat 393. Their A35K config seats a comparable 382. If you count and remove all of the fourth seats in the middle columns, I think it should bring down the total seat count to only 354.
Their LCC-style A330s already seat 366.
I guess PR is trying to be a hybrid carrier of sorts.