Samsung S Series phones get monthly Security Maintance Releases (SMRs) for 3 years. Not all of these include feature updates. SMRs do however have vital security updates to make sure your phone is less vulnerable to security threats, which come from being the largest operating system and mobile device vendor.

Samsung A Series devices get quarterly Security Maintance Releases (one SMR every three months) for three years.

Hence you're not getting SMRs every two weeks.

What you may of experienced is, if your device sat in a warehouse or retail shelf for some time after manufacture, there may be several updates available and as your Carrier batches the push of these updates, to optimise bandwidth and data usage, you may of received several in a short time, to bring your device up-to-date.