Honestly I'd push back a little on jumping straight to a higher dose — storage issues are a real possibility like calmelk20 said, but it's also worth remembering that reta and tirz work pretty differently mechanically, so a direct potency comparison isn't always apples to apples. A lot of people find the adaptation period on reta takes longer than expected before appetite suppression really kicks in. In my own experience I noticed things shifted noticeably around weeks 6-8, which I wasn't expecting after coming from tirz. Might be worth giving it more time before assuming the dose needs to go up.