"Thats a 3x4 multiswitch not a splitter. Use the 18v port and dont turn off the LNB power in the other STBs. If you turn the power off in all but one STB then you will lose all signal when that STB is turned off. Also the splitters are diode steered…"
"Could be 1 of several things. Firsty whats your internet speed like? Ondemand hasn't got the same compression as Netflix or youtube so needs allot better bandwidth. Have you tried doing a software update or even a reboot of the TV might fix it."