code: function(coords) {
  		var zoom = coords.z;
  		if (this.options.zoomReverse) {
  			zoom = this.options.maxZoom - zoom;
  		}
  		zoom += this.options.zoomOffset;
  		return L.Util.template(
  			this._url,
  			L.extend(
  				{
  					r:
  						this.options.detectRetina &&
  						L.Browser.retina &&
  						this.options.maxZoom > 0
  							? "@2x"
  							: "",
  					s: this._getSubdomain(coords),
  					x: coords.x,
  					y: this.options.tms
  						? this._globalTileRange.max.y - coords.y
  						: coords.y,
  					z: this.options.maxNativeZoom
  						? Math.min(zoom, this.options.maxNativeZoom)
  						: zoom,
  				},
  				this.options
  			)
  		);
  	}
docs: Modified L.TileLayer.getTileUrl, this will use the zoom given by the parameter coords instead of the maps current zoomlevel.