Resid permit (<5 year non EU citizen) and business trips

[andrr]

Dear all, please advise.

I have my own company in Czech republic and have a temporary long term residence permit for the own company business needs. I am non EU citizen, lived in EU for 1 year and this permit definitely allows me travelling in other EU countries during 90 days each 180 days.
The questions are:
1) if this permit allows me going to another EU country for my company services provision within the same period of 90/180?

2) Do I understand correct that I need a Van Der Elst visa only for a project which lasts more then 90 days in 180 in an EU country if it's not CR or I will need such kind of visa for every single business trip?

thanks a lot for any opinion!
andrr