i have had this happen to me as well and have allways been paid for the extra work but things are getting tight and i expect customers to start nitpickingX2, i write it up as an extra. It is extra work IMO and i treat it as so, customer cannot expect you to lose time/money for unforeseen problems. I broke a lug off in a meter socket this spring when upgrading the wire from the meter socket to the dis-connect "meter socket was new and live, dis-connect was new", i charged the HO for a new meter socket but only removed the lug that i needed and installed it in the live socket. Yes it was unforeseen, NO i just couldnt buy the lug that day, NO i didnt over tighten the lug as it was installed by someone else, Yes i repaired the problem correctly. Now this repair took a good hour to do as i had to unhook my trailer, find a new meter socket in town, dismantle the socket and then repair, no way was i going to flip the bill. Sorry for the long response.