I never use the marks on the belt as an indexing aid. Those belts are made by too many different companies employing who know what methods of quality control. Just make sure all three sprocket marks align with their respective marks on the engine case and rear timing belt cover - that's all that really counts. And to make it even simpler, if you have the cam-driven distributor on the back of the head, you can ignore the timing of the intermediate shaft all together. In that case you only have two shafts that need to be on mark - the crankshaft and the cam.