MX-28AT motors slowing down

Use the following template to help create your post:

  1. State the model of servo you are using.
    MX-28 AT protocol 1.0

  2. Add (or create) Tags to your post with the specific model of your product.
    MX-28AT motors -3

  3. Describe your control environment. This includes the controller or interface, computer and OS, and any power source you are using
    U2D2 controller , HP-i5 and Windows-10 , SMPG Source(by Robotis) MATLAB AND SIMULINK.

  4. Specify the operating mode you are using, for applicable models.
    Joint mode.

  5. Specify and link any manuals or resources you have used related to your inquiry.
    I have used Dynamixel SDK files for MATLAB
    When I didn’t succeed I used third party libraries in Simulink

  6. Include pictures if possible. This can help our members see how wires are connected, how hardware is installed, or to identify other possible issues.
    My issue- am working using position control on my Dynamixel in MATLAB (2021b).
    Let’s say I am moving from 2000 → 2512 using a cosine (trajectory) function.
    I gave a loop where initially 50 points were generated from 2000-2512. When I increase the number of intermediate points to 100 , the motors slow down i.e., the same 2000 → 2512 takes more time than earlier.
    So my point is, even though I increase intermediate steps (keeping in mind the resolution of the motors 0.0879 deg) I should finish the motion within the same time as in the case of less intermediate steps. How can I get this? Where I am going wrong?

I tried using sync write as well but with each servo an additional 10 sec delay was being added to finish the given motion. How to overcome these issues?