Do I need to add nutrients to a premixed soil?

I’ve used ocean forest soil, which is the same concept. I would def begin to add a small amount of bloom nutes....however u choose to do it, either top dress dry or go the liquid route. That’s if the plant is vibrant and not showing any signs of deficiencies. I really took it easy on bloom nutes and about 4 weeks into flower my plants started to fade a bit and a few yellowish leaves w/ brown spots began to pop up. I’ve concluded that the plants were hungry and needed more than I was giving them. This was very recent and they should be ready for a watering tomorrow and I’m adjusting the feed levels accordingly. If I had it to do over, I would have introduced a the same light dose of bloom nutes, but done it 2-3 weeks prior. Good luck.