Need help with Jump Bar

I have a simple 2d runner game I made in Unity, and for the most part everything works fine. There is one problem though: in the game, there is a jump bar that fills up and then recedes repeatedly if you hold down on the screen. In certain devices, like iPads, the game runs a little bit slower and the visual aspect of the jump bar gets stuck in one position. The variables behind the jump bar still work, and so the game itself works fine, but the jump bar getting stuck is just too annoying for me to want to release the game for iOS just yet.

I have the jump bar set up so that its animator has several one frame animations for each position of the bar. A script passes an integer to the animator to tell it which one frame animation to show. Basically, when someone starts holding down on the screen, the integer goes from 0 to 1, and the animator makes a transition from single frame animation 0 to animation 1 on the condition that the int is 1. Then there is a transition from one to 2 on the condition that the int is 2, and so forth.

Does anyone know a better way of doing this? As far as I can tell, when the bar gets stuck it is because the animator does not make a transition fast enough and then inevitably can not move through the other transitions. The reason I have it set up this way is because I want the bar to stop where it is, then reset as soon as the person stops holding down on the screen.

A better question to ask would be: how do you execute multiple animation clips from a single script?