I looked at the implementation of #linesOfCode of ClassDescription. It is actually wrong, a correct version should be:

linesOfCode 
"An approximate measure of lines of code. Includes comments, but excludes blank lines."
| lines |

lines := self localMethods inject: 0 into: [:sum :each | sum + each linesOfCode]. 
^ self isMeta not
ifTrue: [lines]
ifFalse: [lines + self class linesOfCode]

Cheers,

Roby