It sounds like the SC default values are not valid in your setup. A big number when you are using inch measurements should flag a possible problem.
There was a discussion on default values a month or so back which may relate to your issue. The conclusion was that the Russian developers tend to treat default values as any bad value, where those in this part of the world treat defaults as a value to get you close. After that discussion I treat any 'default' SC value as invalid until checked. Hopefully at some point SC will either use true default values or leave the field blank.
Back to your problem, I would change the value to something like 10 and all should be resolved.