A sealer's function is to temporarily inhibit the intrusion of staining agents into the pores of the stone. End of list of performances. So a sealer will basically be temporary protection from staining agents.
I think it is important that you know how porous the stone is for your own sake.
While some sealers are very expensive and formulated with the highest quality resins. It is really the stone that dictates what sealer and application process is used.
I think that any well known sealer will work with the proper application.
If you started with the stone tech impregnator pro stick with it. Test with water the porosity of the stone prior to the second coat. Then test 24 hours after the second application and see if the porosity is less.
The water test is done using a palm sized puddle of water.
Leave it on the surface for 10 or 15 minutes wipe it away.
If there is a darker mark left it needs to be sealed.
Take it from there.

Thanks for this advice. I tested it with water after the first coat and the water pooled on top.

And just to clarify - the counter top isn't sealed yet so we could do any sealer. I was testing a sample of the slab that has one coat of the DuPont sealer.

Just wanted to add-test the stone unsealed to see how porous it is. This way you will be informed about your stone and see the difference when sealed properly.
There are so many sealers out there it can get confusing.
Some give warranties but lots of fine print.
If your fabricator is recommending the DuPont product I think you will be fine.
I think the Macaubus quartzite is a great stone.
I don't think it is very porous and will serve you well.

This post was edited by srosen on Sun, Jun 9, 13 at 10:33

Thank you! Yes I tested an unsealed sample too. The oil definitely seeped in and left a mark that is slowly going away.