Plaining wide surface issue

Started surfacing wide blackbutt - 300 x 50 using a Carbatec planning bit ( ?) about 30 or 35mm diameter. Taking off about 1mm max per pass and keeping the bit sharp with a credit card diamond sharpener



The surface is OK - there are faint lines on the right hand side of each pass - going across the grain - sled is square & level to bench AFAIK.



Sanding after initial 40 grit on an orbital then with 120 on a palm sander leaves a fine finish to the feel BUT against the light there appears to be some banding.



Is this going to just need a bit more 40 grit sanding before final sanding so nothing shows under the clear satin varnish finish. The pieces are to be used as feature capping 1300 stub wall & 1300 high waterfall end piece.



Any comment appreciated



Thanks

UPO -Richard