Can't wait to see the flowers fully open. Looking good so far! BTW: I agree with Ernie and Rick. IMHO, that plant is suffering from extreme pH induced nutrient imbalance. It may be that some nutrients are not available or a combination that some are now too available while others are not available at all. Fix this problem by repotting. However, in the meantime, to get it started on the road to green leaves again, I'd top it with oyster shell or sifted limestone screenings and water it copiously. What I mean by that is to set it up where a hose can be gently flowing into the top of the pot for at least 30 minutes or so. This will flush out and replace all the high acid moisture that is currently contained in the pot. If the water is on the cool side (not cold!), the calcium will disolve from the oyster shell or limestone and help to buffer the pH up a bit. Calcium is cold water dissolvable. Follow the 30 minute flushing with a normal strength of fertilizer solution with epsom salts added at the rate of 1 tablespoon per gallon. This will help the plant to take up nitrogen, which should also aid in putting the chlorophyl back into those leaves. Keep in mind: it is impossible to give a strap leaved Paph too much light if it's growing under lights....even HID lights. This statement is true however, as long as the other cultural elements are correct.....such as watering, fertilizing and pH of the medium/water. Yellow leaves mean less or no chlorophyl, which means less or no photosynthesis, which means a weakened plant. To get the most from the plant, the chlorophyl must be adequate enough to give the entire plant a nice, healthy, medium green colour.
All this concern is just that; it's just concern. Obviously, the plant is not at death's door; but, there is room to improve culture and therefore, the flowers the next time around. So, if you like the flowers now....and you get the plant to green up nicely before the next blooming; you're going to LOVE the next blooming! Good luck! It would be great to see how this plant progresses over the next year or so. Would you please post photos of it periodically for us all to see the process of greening up and the resulting next bloom?