when he gets a call from multiple staff in the same day, he gets frustrated and says 'why cant they figure this out', but to each of them, its individual issues so they dont see it as a grind on the payroll person.
It can be a grind and the goal post can move back, side to side, and forwards at any given moment. you may apply to 10 jobs that are the same, get all 10 interviews and not get a single job offer. Once again, this is not based on YOU but each company have slightly technical differences.
I'll use another example: the company i work for submits proposals to ongoing contracts from a municipality. The first one, they made it past the technical requirements, but turned down on the financials. Second time we didnt even pass technicals. Third time again we made it past technicals but lost out in the end. All of them had the same RFP and each time there was a different management team on the client side making the decisions.
Keep at it because when you do find that job and land that offer, it'll all be worth it.
Btw, million dollar question to ask during an interview:
"is there anything on my resume or during our discussion that would cast doubt on why i wouldn't be the top candidate for this role?" Boom, headshot right there.