The chili plants not growing that much now probably has nothing to do with them budding, but rather the amount of light they are getting from the florescent lighting. Even though they do expend a lot of energy to grow the produce. But they are continuously fruiting plants and are able to do both at the same time.
Florescent
lights don't work well with tall plants because the farther away the leaves are from them the light, the light intensity drops significantly (especially in comparison to
metal halide and
high pressure sodium lighting). A few inches can make a huge difference in that regard. So even though the tops are close enough to the lights, the lower portion of the plants are likely not getting sufficient light. That would cause the growth to slow down and probably even stop, because they are not getting the light they need for photosynthesis and growth.