Bowling shoes were originally designed with a rubber heel and leather sole on the sliding foot and rubber heel and rubber sole on the non-sliding (push-off) foot. The rubber heel on the sliding foot acted as the brake, so to speak, to stop your slide at the proper time. Most of the weight at the beginning of the slide was on the sole and then the heel would drop.
With the advent of adjustable soles and heels, you can pretty much adjust them for whatever amount of slide you want or don't want.
For a planter (I am not one, so take this with a grain of salt) I believe you are doing it correctly if you are using a normal bowling shoe without adjustable soles. You don't want to slide so you should land on your heel first.
Other planters may be putting their sole/toe down first if they are using a high friction sole and thus don't have to worry about it sliding on them. (Adjustable sole). Again, just my opinion which is absolutely worthless in the real world.
This sounds right to me. When someone I see that is sliding (all but running a 4-step delivery), they will slide on their sole, but then use the heel to stop the slide (not abruptly, but like you're braking when coming to a stop sign or a red light). Their natural momentum keeps them in balance so they don't keep going after their sliding foot is completely planted.
By contrast, there's a 2-handed bowler in the age bracket above my kids in their youth league. He wears his street shoes for his bowling shoes, so as fast as his approach is, when he plants his foot at the time of release, he is always falling off balance. And I mean
ALWAYS. He has no slide because of the street shoes, but because he would slide on his heel first, his ability to stop his momentum is completely gone because of the rubber sole so to keep from fouling he's off balance and falling off all the time.
He's also the type that doesn't appear to want any instruction so he's on his own there. But from what you describe above, that sounds like the proper way to slide, and how I've seen others slide when watching them bowl.
BL.