this can be done with math instead of a loop (untested):

using division:
```
var steps = Math.floor( ( this.options.max - this._valueMin() ) / this.options.step );
this.max = this._valueMin() + ( steps * this.options.step );
```

using remainders:
```
var remainder = ( this.options.max - this._valueMin() ) % this.options.step;
this.max = this.options.max - remainder;
```