I was told that because Grand Distinction has a “primer in it”, I can paint right over the old paint without priming. Is that true?
Yes, as long as the old paint is of the same type. Example- the old paint is acrylic or water based. All paints are self priming over same type of paint. The idea that a paint has a primer in it is a marketing ploy to increase sales.
All good paints stick very well (including Pittsburgh paint), primer included or no primer.