Houdini change position based on last frame position

Question

I am trying to procedurally animate things in Houdini, using similar logic as in Unity, moving the object based on its current position, i.e., NewPosition = OldPosition + Direction * Coefficient.

Using the Vex code below inspired by this post:

vector @posRecord[];
// ... 
if (@Frame == 1)
{
    @P = {0, 0, 0};
}
else
{
    vector lastPos = @posRecord[len(@posRecord) - 1]; 
    v@lastRead = lastPos; 
    @P = lastPos + @N * 10; // @N as direction 
}

append(@posRecord, @P);
if (len(@posRecord) > 10)
    removeindex(@posRecord, 0);

I am able to record the position, but lastPos cannot properly read from @posRecord. In Geometry Spreadsheet lastPos keeps being 0. As a result, the object is merely reading the @N as XYZ positions instead of move based on @N.

What is going and is there a way to fix this?