PPG certified painter here. i paint 3 stage pearl all of the time. also paint 4 stage Mazda paint a lot also. i THINK a few other manufacturers also have 4 stage paints also..

the paint you mention isn't exactly like you think it is. the base coat isn't just white out of the can it is a specific mix of base color to get the final result. a lot of 3 stage white colors don't start out with a completely white ground color. also there are other additives in the pear stage coat other than base coat clear and basic pearl tint. some colors have 3, 4, and 5 different color pearl tints in the pearl coat. also a lot of manufacturers are also adding specialty pearls to the mix in addition to basic pearls you think of.
i use PPG waterbase coat, i do believe there are about 20 different pearl tints in the mixing banks.


you CAN just add some pearl tint to base coat clear and spray over a white base color. i will warn you the results might be different than your expectations.
i would suggest spraying out a color card to test what the final color will look like before spending a LOT of $$$ and not get what you want.