Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 40; Flight Crew Total 4300; Flight Crew Type 125
Communication Breakdown; Confusion
ATC Issue All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification
Environment - Non Weather Related; Staffing
There was moderate turbulence all altitudes. I asked the prior controller to let me know when turbulence had lessened at higher altitudes so I could climb as I was at FL280. The next Controller cleared me to Flight Level 400. I confirmed the climb to 400. At about 36;600 feet I was asked by that Controller on frequency XYY.Z whether I wanted FL400 or FL360 or similar words. I remarked back that I was already cleared to FL400. He didn't respond. This Controller was very busy because everyone was asking for a different altitude. I confirmed the altitude assignment and before he even cleared me there he asked if I wanted that altitude. It was the only smooth altitude at that time.I think the best way to correct this is for the Government to get back to work and live with COVID. They were short staffed.
High Performance Aircraft Single pilot reported receiving confusing instructions from the Controller and believes COVID-19 ATC staffing issues were a factor.