I got unopened 18 L of 5100 Nippon Wall Sealer from a friend. So far I have no plan for repaint my outside. I'm planning on using Nippon interior top coat for my interior wall. And I looked at technical data sheet for Nippon 5100 and 5400 wall sealer, only different I see is finishing, 5400 which can use both interior and exterior got matt finishing. 5100 got mid sheen finishing. So here goes my question.

1. Is is okay to use 5100 as interior sealer with interior nippon top coat?
2. It is okay to use 5100 as only coat? Im planning to use it on my ceiling without additional top coat.

Thank you in advance.

Yes....sealer is also use to cover water leaking stains on ceiling.

Colour won't retain for wall sealer, it's not OK to use as final coat for ceiling. It will go yellowish after some time.

1. 5400 finer finish. But both can work as interior sealer.
2. No. Sealer doesn't look nice on its own. If u use on ceiling the matex 18L white (the cheap rm60 big pail) to finish is best. Easy to apply.