Allen,
An active and knowledgeable operator with a chainsaw will sharpen the chains till the teeth are almost gone before retiring the chain. I've always found the chains stretch the most at first, then settle down and don't change length much.
It is standard operating procedure all around the world to make up chains from bulk 100' or 250' long reels of chain and the regular chaisaw places charge by the connecting links, say 22 cents a link.
Anyway, the shortenting by a link is fine.
That said, you mentioned Still chainsaws, and they would come with Stihl chains, which are recognized as some of the very best available. So why would this happen?
The engineer in me says something funny is probably going on, but don't know what. The simplest thing is to replace them, and they would only run about $14 each or so at baileysonline.com.
Rich S.