I'd prefer that explanation as well (why would the Link forgive Odo so easily?). There's just one thing there that smells a bit fishy...
...Quark sells it to Odo for eight slips, after minimal haggling. Would he do that if he weren't already being paid much more handsomely by somebody who wanted the lump of goo to be delivered to Odo?
Check the Memory Alpha entry for what eight slips would otherwise get you. An elevator ride, or 80% of a root beer case, is the going price for a Baby Changeling?