How do I use platform vector Y?

Hi, I am using the function "set platform vector Y" to make my own jump system, but I have one question.

To jump, I use a custom sustain system with a timer, so when the jump button is down and timer is not over I apply a vector Y to the body to jump higher or not. The problem is that sometimes the body makes a great jump, I don't know why. I am using delta seconds on the vector, because is a continued action while the button is down.

Do I have to use the delta time or the use of vectors uses internally the delta time??

Edit:

my code is something like:

If(jump_key is down) -> apply vector Y (body.jumpstrength * body.jump_strength_bonus * dt)

VectorY is in pixels/seconds. Every where you see 'second' it is already dt corrected. Like every 3 seconds, also dt corrected.

&

Say you want to jump max twice in height ... then body.jump_strength_bonus cant be bigger then 2

VectorY is in pixels/seconds. Every where you see 'second' it is already dt corrected. Like every 3 seconds, also dt corrected.

&

Say you want to jump max twice in height ... then body.jump_strength_bonus cant be bigger then 2

Thaaaank you so much, so I deleted the dt from the formula. I was afraid that in some computers the player could not reach some points.

thanks