1. but if an adverb, why is is separated from the verb it modifies???

2. then it would be written: "The office can well handle four hundred applications per day"?
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To me, it's similar to:
"I got angry and, well, I hit him." where 'well' has the sense of '...and, OK I admit it, I hit him.

I can't get passed that I see it as an interjection. Its meaning in the given sentence might be:
"The office can handle, I think / in my opinion/ I'd say, four hundred applications per day"?