The change in sound shows where your pulse is still unsteady
The sequence doesn’t increase the tempo, but the number of tasks. First you look for a striking surface, then you repeat it regularly, and finally you change it under time pressure. That’s why the fourth step can become unsettled even though you can manage both sounds individually. Prepare the next hand shape while opening your hands, not just before contact.
A typical mistake is using a larger backswing for the clearer sound. Your hands then have to travel farther, and you speed up briefly just before the beat. Keep both variations at roughly the same height in front of your torso. Keep your elbows relaxed and your shoulders down. The brighter sound comes from the contact, not from raising your arms.
The groups of four here are just practice segments, not a complete Flamenco compás. Only when you apply them to a palo do its rhythmic relationships come into play, for example in a Marcaje for Flamenco Tangos. For this Palmas sequence, keep your feet still for now. If you want to add foot sounds later, understanding the difference between Planta and Tacón as foot contacts will help you keep the two tasks distinct.

