I don't think you'll need to go that long at that level of PPMs That's a good starting point to get your plant feeding again, but a good indicator that it needs more nutrition is the amount of solution it's consuming. So keep a close watch on the total volume changes each day. If it's going down, then it's feeding and probably wants more nutrients.If the signs of deficiency don't show again I'll keep same ppm for a couple more weeks before raising it again.
One method I like to use is to pre-mix a solution at about twice the level of PPMs that it's currently at and then top off the water with the more concentrated solution. This creates more "buffering" to allow the plant to acclimate to higher concentration levels over time. So, you might mix a solution up to a level of about 650 PPMs and then top it off with that over the next week.