The loss across a splitter is just about original/number of splits, if I remember correctly, i.e. a 2-way cuts the signal in half.
A number of splitter characteristics can affect signal quality: the quality of the splitter; the bandwidth of the splitter (you want like 10-1100 Mhz); certainly the number of splitters; the quality of the coax and connectors between splitters, etc.
Best thing is to ask the cableco to come out and check things over. They can measure the signal at the drop and take it from there.