You might be surprised. The rule of thumb, given modern run-scoring numbers, is that scoring 10 additional runs during a season, or equivalently saving 10 runs on defense, adds about 1 win. As you note, those runs aren't all going to occur just when you need them, thus the high ratio of extra runs to winning outcomes.
The OP spoke of 18 missing runs, so that could be good for a couple of extra wins so far this season, in that light.