That sounds right.....
The odd thing is the only thing I can think of that would cause the fuel pumps to draw excessive current from the relay is some sort of blockage, forcing the pump to work the motor harder than ususal.
Maybe the fuel filter was clogged? or there was some other blockage in the line that caused a flow restriction, which was causing the pumps to work overtime?
I have never heard of a motor just randomly drawing too much current. Ususally the current of a motor is a function of the mechanical load placed upon it.
There is also some fused mechanisms here where if it was drawing huge amounts of current, it would actually blow the fuse. I havent seen the 420 SEL's fuel pump relay, but some mb relays have a fuse atop them.
The relay was definitely bad, the pump on the other hand - I'm not sure if it was bad or not.
Regardless for the work you had done it's a decent deal. And at least this way you wont have to look at the fuel delivery system for a while.
1990 500sl R129 - 76k Original Miles - New project - Follow the saga http://90r129.blogspot.com/
1990 190E 2.6 148k mi (sold)
1989 420 SEL 246k mi (sold)
1995 C220 175k mi (sold)
1992 190e 2.6 74k original miles (sold)
2000 c230 Kompressor 122k miles (RIP)
1996 C220 149k mi (sold)
2000 C230 Kompressor Sport 127k (sold)
2009 Mercedes c300 4matic
2006 Mercedes s430
2005 Jaguar XJR
2003 Cadillac Escalade