Financial verification makes sense to me. INZ need to know that a business providing a skilled job for a new Resident is on a sound footing and not likely to be about to go under. SM6.30.10.e.
https://www.immigration.govt.nz/opsmanual/#66791.htm It's possible that there's a requirement that they keep updating that information during processing (as the national economic climate could affect the employer's situation, e.g. during the current pandemic regulations), but ten times in the course of two years does sound rather odd.
The only reference to 'Verification officers' I found on a search was from two years ago, in connection with partnership visas, and that doesn't sound as though it has a bearing on your case. Maybe EGoodhue or any other ex-INZ CO can shed some light on this?
Notice, a CO doesn't have to go through you, necessarily, to work on your case. If there are matters they can check with third parties, e.g. your qualifications, work history, partnership status, you may not hear anything about that. There have been instances that the first an applicant heard about their processing was that the file had been sent for 2pc, which is an extreme case and shouldn't happen, only it sometimes does.