I would like to see the sentence written as: (please, comment)
The side by side screenshot you have posted makes no sense compared with the Zround scoreboards page**;** but looking at your screenshot of the Zround message setup page**,** I suspect that you can use whatever you like as the command string at the start of the message rather than them being fixed as I
I don’t know the grammatically technical difference between “posted” and “have posted” but in this case I think the plain “posted” is more correct. It is a simple statement of something done in the past. However “have posted” is certainly not seriously incorrect or confusing.
The other change from “had” to “have” changes the meaning - it is not simply a grammatical change. “Had assumed” describes a situation at a time in the past (without stating whether or not the situation is continuing). “Have assumed” describes a continuing situation.