Looks like she is lacking a little in N but i wouldnt worry too much, seems to be only affecting the older fans which always will lose color/fade during flower and no signs of any other serious deficiencies. Looks to me like she has been flowering for at least 4 weeks going by the pistils, during the flowering phase you dont want a whole heap of N in the mix, I would simply keep going with what you are doing, will need to feed a bit more often as the plant grows but as for strength id stay as is, looks about right by looking at leaf tips, any stronger might cause some burn this late. Saying that though its hard without any info, how far along? what nutes do you use? how often do you feed? setting PH? what strengths etc.