Spongy brake pedal

I have a 2002 Focus SE, NON ABS brakes. I just replaced the pads and rotors myself. I didn't open the system but did lose a minor amount of brake fluid from the cap when I pushed the pistons back into the caliper using the same procedure that I have on many other cars. After finishing, I found the brake pedal was spongy / soft. I thought this would go away after running for a few minutes and braking during a test drive. It did not. I bled the brakes myself the next day to no avail. Still thinking it has air in the system, which is the common reason for a spongy pedal, I took it to a brake shop where they flushed and bled the entire system .... again, to no avail! I took the car into the dealer two days ago and after flushing the system 4 times! and inspecting it for problems including my install job, no problems were found. They called me today to indicate that it was "ready to go". I drove less than 1 block from the dealership and realized the same spongy pedal problem existed. I took it right back to the dealer and now they are saying I installed too soft a pad which is BS. The old pads were about 70% so I sent them back to the shop with the courtesy driver so the shop could reinstall them to see if it would make a difference. (The rotors were shot, that is the only reason I replaced both pads and rotors). Dealer service personel have called the Tech line with Ford and have not been given any reason for the soft pedal. The dealer service manager tells me while the pedal is soft, they are safe. This is my step daughter's car and I don't want her having an accident from this. DOES ANYBODY HAVE ANY OTHER IDEAS OR HAD SIMILAR PROBLEMS WITH THEIR FOCUS HAVING A SPONGY PEDAL????