Preflop raise amount

[Hattifnatt]

I play 6-max NL usually 2/4.

I almost always raise 4 bb + 1 bb per limper. to $16 first in, $20 with a limper etc.

If I raise from SB, BB with a decent hand that I think is the best, like AJo, I sometimes raise a little extra to make the possibility to win the pot right away bigger.

That this sounds like a good approach? Other thoughts?