I’m not medically fluent to know what immediate release vs time release is exactly. But my general googling suggests that the Gabapentin tablet I take can take 2-3 hours to “kick in”. I worked gradually up to 800 mg 3x a day to find my optimal spot, where I’ve been about 6 years at that level. I feel I maintain a good comfort level with little if any side affects with the pills spread out evenly. I look at it as keeping the medicine flowing at an even level. In the event I miss a dose, my body usually lets me know with a low level nerve pain starting in my legs after 2-3 hours. When I finally take the missed dose, it seems to take a couple hours for my body to return to the even keel it was used to. I’m ecstatic when I realized I missed a whole dose without my body realizing it, but that’s rare. For me & my Gabapentin type, I’ve learned my body does best on the 3 even doses a day. Some can enjoy lower doses at more frequent intervals but I know that it would be a scheduling challenge for me to have more time slots. I’d work with your doctor to find what helps you stay more comfortable and stable!