I too was a splicer in the field, in many rebuilds I was involved with I was given a blank strand/trench map, broadband calculation book, and a caculator. Trust me when I say this, 20 feet of cable will not affect your levels enough to complain, for that matter you could be 150 feet off and still get levels, given you know about splicing and activation. The problems that people blame on designers more often than not, are problems that should be blamed on project managers, walkout crews, and splicers that think they know what is going on, but can't remember what the loss is on the specific cables they are working ( a must if you are going to be figuring out what your levels are susposed to be as compared to what you have). NO disrespect, but I would pay more attention to your splicing and activation skills if I were you.