Just ask they paint staff at the store - it most cases they'll be able to advise. If not, follow the instructions I guess.
I know you aren’t in the US but there’s less than 1% chance that the person behind the paint counter at Lowe’s/Home Depot knows anything about the paint he/she is selling. I’d have to go to a specialty shop for that and then a gallon of paint would be around $70 instead of the $50 I paid.
Whenever you or bobby post about your locations it makes me want to travel. NJ is nice but it beats you down…
When I say ask at the paint section, I'm thinking about an Australian Bunnings store or similar place. They have staff dedicated to each section, so they usually have some reasonably experienced people working in relevant areas. Not always of course, but I know enough about paint generally to gauge whether they know their stuff.
Obviously I don't know your US paint stores, but if getting the right advice means you pay $70 instead of $50, it may be worth it. You can always buy the next tub at the cheaper place.
That asking advice strategy is pretty useless in rural Thailand - most of the "tradespeople" here have relatively little experience, or only experience relevant to painting a house. Aside from the difficulties of talking about these technicalities in a second language, the staff employed at the bigger hardware stores are usually inexperienced kids who will just recommend some completely inappropriate product. I often just have to do my own research and buy online (even paints/oils) as the local stores won't even have it.
We built our own house here and I miss Australian tradies. I'm a soft-hearted guy but I've had to sack more than one Thai painter that can't be bothered learning things like loading less onto the brush and backbrushing (y'know, working the colour into the wood, rather than leaving a layer on top). Takes a little longer, but then you see the woodgrain rather than an opaque layer of stain that will peel off once a bit or water gets under it. Some people think because they painted in pre-school they are somehow qualified.
These are some of the prices we pay to live in Paradise