I can see a couple of things that may be involved. First you may be experiencing problems with UV transmission through the glass that you installed. Some types of glass transmit UV better then others. Typically glass effect in the UV spectrum that you are utilizing will not be as great as the far band UV would be for instance.
The other matter that may be involved is that the fixture that you bought from Kmart has a ballast of some type in order to fire a fluorescent bulb. The bulb that you replaced it with (BL from Bulbman) may not be properly matched to the ballast in your fixture.
Not knowing what wattage lamps that you are using, what the thickness and type of glass that you have installed makes it difficult to determine the cause(s) of your lengthy exposure times.
Additionally there is the matter of negative density. If your processing has departed from your previous procedures and led to a greater negative density then times will be increased. A .30 increase in density will cause a doubling of exposure times. Do you have a densitometer or have access to a densitometer? That may be a good place to begin...unless you have already compared using the same negative for your equivalent exposure times.
These are all things that I would check into in order to arrive at an answer. Good luck.