Is there a tax reason for why health insurance premiums are processed this way?

For several years, I had noticed that my health insurance provider would delay processing my paid premiums, and I would not infrequently receive a statement stating that a payment had not yet been received. I give a recent example below.

Subsequently, I have switched to two other health insurance carriers and have seen the same behavior. Is this standard practice in the health insurance industry? Is the practice mandated by tax laws?

Here's an example.

1. I received a bill that stated that a payment was due by 1 Oct 2007 (happens to have been a Monday).
2. I instructed my bank to send a payment so that it is received by the prior business day (Friday, 28 Sep 2007)
3. In this case, the payment is NOT sent electronically, rather it is sent by the bank using a paper check.
4. The bank guarantees that the payment will be delivered by

28 Sep, and will back me up if it is not.

1. The insurance carrier claims to have received the check on 1 Oct 2007, which was the due date. Of they may have actually received the check on Friday, but not recorded it until 1 Oct 2007.
2. The bill I received for the 1 Nov 2007 payment stated that the 1 Oct 2007 payment had not yet been received.
3. This occurred because the insurance carrier cut the bill for Nov on 9 Oct 2007 but did not credit my account until

13 Oct 2007, 12 daze after they admitted having received the check. I've seen this occur repeatedly with at least my last 3 health insurance carriers.