I agree with FP.
Adding weight has the same effect at lengthening the arrow (shooting one cut longer). If you use a .500 shaft, adding 100 grains of weight, is approximately the same has adding 2" to the shaft. Or, +50 gr. = 1" longer. With some bows, this is approximately the same as going up in weight by 2 lbs.
If you replace the inserts and add weight, the increased weight (11.5 gr) may not have any affect on a fletched arrow, possibly 1/4" on a bare shaft. The slightly longer insert may have no effect. Weight tubes will cause the shaft to drop and will have less effect on the spine.
When you have the correct spine and weight, a bare shaft and a fletched arrow should hit at the same point on the target, at 20 yds. Weaker shafts with +50 gr weight will hit roughly 6" to the right, +100 gr weight will hit roughly 12" to the right. This can vary depending on the bow and set.
What this means is, if you have the correct spine, the fletch and bare shaft will shoot the same; adding weight, going to a longer arrow, or a weaker spine will shoot to the right for a right hand shooter. If you need a stiffer shaft, reduce weight, shorten the shaft or go to a stiffer shaft.