How long do I have to wait before being able to go back to Shenzhen again with another Special Economic Zone visa? And how often can I do so?

From what I have read and been told so far, same day re-entry is fine, but I'm getting conflicting information regarding how often one can obtain the Shenzhen 5-Day Visa on Arrival.

When I asked a Chinese immigration officer while doing the Shenzhen 5-Day Visa on Arrival in December 2018, I was told "you can obtain the visa no more than 3 times per month" and, once I repeated the question to confirm the information, the second answer I got the same officer was slightly different: "less than 3 times per month". So it was unclear whether 3 times would be ok.

Furthermore, someone on reddit reports having lived over 3 months on 5 days SZ visas:

You can come back same day if you want, I lived over 3 months on 5 days SZ visas, have over 20 of them in my old passport. Crossing the border at Luohu and immediately returning back applying for a new 5 day visa. Never had a problem.

In summary, same day re-entry is fine and twice a month is fine, but I'm not sure yet whether one can enter more than twice a month. The visa currently costs 168 RMBs for French citizens (the price depends on the visa applicant's citizenship; 168 RMBs is the most common price).