i think he is worried about it not being so vibrantly green ? if it's just a little lack of light wait it out till it's sunny again. and see if it greens up the new leafs look a little jagged.. but that's prolly nothing right?
I can't think of anyone who wouldn't envy you! This is one nice plant!!! Don't worry, it's absolutely normal for them to grow slowly, but everything looks absolutely perfect!
It's been told that Chinense species can be slow growers, particulary Naga. If you want it greener: increase light, increase nitrogen, or spritz it with some epsom salts (1 tablespoon per gallon of water).