Accel and Decel physics

[Erayd]

I created code for a platform to get faster each update until halfway and then slow down, but its acting strange. In one direction is speeds up and then only gets two updates to slow down, then the other direction gets 6 or 7 slow down frames.

This is the physics code for the platform, what am I missing or doing wrong?

//Accelerate faster each step up to 50% of the way then decellerate
    if(stepCount >= update){
        if((rangeX > 0 && phy_com_x < startX + (rangeX/2)) || (rangeX < 0 && phy_com_x > startX + (rangeX/2))){ //X axis
            if(rangeX > 0 && !readyX) physics_apply_force(phy_com_x, phy_com_y, phy_mass*(pushX + diffX), 0);
            if(rangeX < 0 && !readyX) physics_apply_force(phy_com_x, phy_com_y, phy_mass*-(pushX + diffX), 0);
            if(diffX + accelX < terminalSpeed) diffX += accelX;
            else diffX = terminalSpeed;
        }
        if((rangeY > 0 && phy_com_y < startY + (rangeY/2)) || (rangeY < 0 && phy_com_y > startY + (rangeY/2))){ //Y axis
            if(rangeY > 0 && !readyY) physics_apply_force(phy_com_x, phy_com_y, 0, phy_mass*(pushY + diffY));
            if(rangeY < 0 && !readyY) physics_apply_force(phy_com_x, phy_com_y, 0, phy_mass*-(pushY + diffY));
            if(diffY + accelY < terminalSpeed) diffY += accelY;
            else diffY = terminalSpeed;
        }
        //Decelerate after reaching the halfway point
        if((rangeX > 0 && phy_com_x >= startX + (rangeX/2)) || (rangeX < 0 && phy_com_x <= startX + (rangeX/2))){ //X axis
            show_debug_message(string(phy_speed_x));
            if(rangeX > 0 && !readyX) physics_apply_force(phy_com_x, phy_com_y, phy_mass*-(pushX + diffX), 0);
            if(rangeX < 0 && !readyX) physics_apply_force(phy_com_x, phy_com_y, phy_mass*(pushX + diffX), 0);
            if(diffX - decelX > -terminalSpeed) diffX -= decelX;
            else diffX = -terminalSpeed;
        }
        if((rangeY > 0 && phy_com_y >= startY + (rangeY/2)) || (rangeY < 0 && phy_com_y <= startY + (rangeY/2))){ //Y axis
            if(rangeY > 0 && !readyY) physics_apply_force(phy_com_x, phy_com_y, 0, phy_mass*-(pushY + diffY));
            if(rangeY < 0 && !readyY) physics_apply_force(phy_com_x, phy_com_y, 0, phy_mass*(pushY + diffY));
            if(diffY - decelY > -terminalSpeed) diffY -= decelY;
            else diffY = -terminalSpeed;
        }
        stepCount = 0;
    }

//Changing states
    if((rangeX > 0 && phy_com_x > startX + rangeX) || (rangeX < 0 && phy_com_x < startX + rangeX) || (rangeX == 0)) readyX = true;
    if((rangeY > 0 && phy_com_y > startY + rangeY) || (rangeY < 0 && phy_com_y < startY + rangeY) || (rangeY == 0)) readyY = true;
    if(readyX) phy_speed_x = 0;
    if(readyY) phy_speed_y = 0;
    if(((obj_Player.platform == id) && (transX && transY)) || ((obj_Player.platform != id) && (readyX && readyY))) changeDir = true;
    if(changeDir){
        readyX = false;
        readyY = false;
        diffX = 0;
        diffY = 0;
        startX = phy_com_x;
        startY = phy_com_y;
        rangeX = -rangeX;
        rangeY = -rangeY;
        changeDir = false;
        transX = false;
        transY = false;
    }

Creation code

///Vars
phy_fixed_rotation = true;

changeDir = false;
startX = phy_com_x;
startY = phy_com_y;
readyX = false;
transX = false;
readyY = false;
transY = false;
diffX = 0;
diffY = 0;
dropAway = false;
oldXSpeed = 0;
oldYSpeed = 0;
stepCount = 0;

//Customizable variables
//Starting push
pushX = 30;
pushY = 30;

//Acceleration
accelX = 30;
accelY = 30;
decelX = 30;
decelY = 30;

//Range
rangeX = 60;
rangeY = 0;

//Top Speed
terminalSpeed = 70;

//Step count to update speeds on (Smaller equals faster
update = 10;