I'm guessing that you've also been using a retinoid or having other rejuvenation treatments because the fact that you're not hearing the "crunch" sound means that either the doctor changed the needles they were using and these are of a better quality, that they're changing the needles as they go along with the injections since it's a dull needle that can make that sound, or that your skin is healthier due to rejuvenation treatments and the needle is passing through healthier collagen as it goes through the skin to the muscle. All of these are good outcomes and you may notice that you have less pain and bruising from the treatments as well.
Coco, Any crunching sound during Botox injection doesn't relate to whether it will be effective. Some doctors automatically inject very deep (perhaps sometimes deeper than necessary) and a crunching sound or sensation may be common especially in the forehead area where the fascia layer (tough connective tissue) is more robust around the thin muscle layer. Whether the Botox or Dysport works is related only to the freshness of the batch and the skill of the doctor, not the actual sound.