Don't worry about it. I use LoRs and personal statements to get a quick look at whether the candidate and her supporters care enough to write a coherent passage. Minor technical errors, yeah, I feel like Dred where it is not 10 out of 10, but at worst 8 out of 10. Now, if the grammar and usage errors are such where I cannot comprehend what is being written, I seriously will dock the LoR for ambiguity.
"I fulfilled my hospital externship at St. Mark's with the geriatric care component scored as outstanding."
(Actual sentence with hospital name changed from this year's batch of statements which is grammatically correct, but ambiguous in meaning. Did this person score outstanding at St. Mark's or on the geriatric component specifically? Fulfilled has the same problem. Turns out it was both after calling the site. For grammar Nazis, this is why English writers should always avoid using multiple propositional indirect objects with a ditransitive verb form as the indirect reference could be either prepositional phrase.)
The minor exception is that I would have a problem with someone misspelling a drug name or dosage form, even long ones like latanoprost ophthalmic, because I feel that looking the term up for precise correctness is a pharmacist's job and should be instinctual at this point.
