Again, I know of no amplified antenna, preamp or distribution amplifier that would require more than one power insertion device. Something was not installed in the ideal manner.
For about the same money, you can replace the omni-antenna with an antenna that needs no power. You'll eliminate the confusion about power insertion and likely have a more robust signal at each TV.
In your situation, you only need to run coax from the antenna to a grounding block, then to a single 3-way splitter, and then from the splitter, a coax run to each TV.
http://forum.tvfool.com/showthread.php?t=901