Can I buy *another* pass during the discount?

Hi, I’m planning a holiday for a couple of weeks and was trying to squeeze all the travel within 7 days in a month. But now it turns out there’s an offer for 50% discount on full-month passes. That’s great! already bought that

Now I was wondering if I can buy another 1-month pass to use later this year. It seems the offer ends in 3 days, and I still won’t have activated the first one. Will that interfere with the current pass or can I “hoard” another one? It seems too good to be true, wanted to check