It's all right. I'm actually switching, first of all, from ports (which I used to build from latest) to pkg and quarterly .If you switch from latest to quarterly already installed ports may be ahead of quarterly ports. It wil disappear after some time.
Doing so because of the downside of building ports from latest tree: Synth rebuilds a lot of stuff on each update, then gets stuck with one port (www/node in my case). I never cared if www/node existed, but lo, NOW it must be used to build Firefox (((.
....So I'll be just fine with quarterly, given my ports get updated no oftener than that in any case. Then, if needed, I'll build some modified ports fr the corresponding quarterly tree. THAT type of flexibility is exactly what I always needed.