Are There Limitations On Apple's Test Users When Testing Renewable Subscriptions?

Not really a programming question as such but I was hoping that someone might no the answer. I'm integrating an Auto Renewable subscription system using MKStoreKit and I'm currently testing the monthly subscription. Now i've noticed that Apple test users seem to renew every 5 minutes up to 5 times.

After that I can renew again but the automatic renewal process seems to stop and does not auto renew. Is this an Apple feature? I'm wondering if I've made a mistake whilst integrating MKStoreKit.