Let's say I have 3 points of movement on slot 1, and 3 points on slot 2. Can I tow the bomb one space forward, and then instead of using the leftover point in slot 1 for normal mech movement, I chain that point with the first point in slot 2. Now I have 2 points for another tow move, and the last two points in slot 2 I use for the tow movement again. All in all, I towed 3 spaces.
Just to be comprehensive, if you happened to be a space away in the first place, then you could use the first slot to move 1 space and then tow 1 space, then the second slot to tow 1 space and then move 1 space.
That's going to be the only way to tow the same thing twice with two subsequent slots of 3 movement.