I have also solved this no turn off problem by putting a filter between each module powering florecent lites in my home - it works. If you use one of the noise measurement units avail for X10, you will likely see 30-50mv of noise at x10 freq when the lite is on, 5mv with it off. With the filter I typically see 7-8mv and the lite again works. You need to use a filter really on every flor. lite in your house to cut this noise or a lot of your x10 stuff won't be dependable.
FYI, 2 40watt bulb flor lite is 80 watts; add a tad for inefficiency and you are still well under 1 amp (85w/120v=0.7amps) so the little 5 amp module is fine for your use. Even for upto 5 of these lites. Good news is the components inside the smart home unit can handle 10-15amp easy unlike the x10 model and it also is well fused (replacement fuses are cheap at digikey.com).
Also, I concur on XPPF x10 little 5amp filtes - DON'T USE THEM. I do not believe they really are UL listed as printed on them - I think the UL listing must be fake on these China made units as not only do they smell if run with 3+ amp load, I almost burned my house down with one at 4.8amp load on florescent lites - the 12" flames luckily blew out of it when I was in the room and could grab the fire extinguisher. It did burn the 2x4 wall stud before I could put it out. I have removed all these cheap units and replaced them all with smarthome units as mentioned above.