Medium Transport
Flight Crew Flight Engineer; Flight Crew Flight Instructor; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 80; Flight Crew Total 14600; Flight Crew Type 230
Communication Breakdown; Situational Awareness
ATC Issue All Types; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Issued New Clearance; Flight Crew Returned To Clearance
Procedure; Human Factors
I had filed a flight plan for FL280. During the climb; a [ZME] Center Controller issued us a clearance to climb and maintain FL300. My FO responded accordingly. We were then handed off to the next sector; so we checked in. As we were climbing through FL287; then Controller said he thought we had filed for FL280; but was it our intention to climb to FL300? My FO responded that FL300 would be fine. So the Controller cleared us to continue climb to FL300. I don't believe we were ever anywhere close to other aircraft; so no conflicts ever arose. I'm not sure why the previous Controller cleared us to FL300 instead of our filed FL280; but it was fine for us so we just accepted it. I'm also not sure why the next sector Controller did not know that we had been cleared to FL300; but I think when we checked in we gave him our current altitude and that we were climbing to FL300; as that is our normal procedure in hind sight; I should have had the FO question the first clearance to FL300 to be sure that's what ATC wanted: perhaps that Controller gave us an altitude he was intending for someone else? At least it would have clarified things 100%. As I mentioned before; there were never any traffic conflicts or safety issues; but the potential was there.  So when we were issued an altitude higher than what we had filed for; we should have questioned it: just to make sure everyone was on the same page. I have noticed in the last couple months; that Controllers seem to be working multiple sectors and are off-line more frequently than was common in the past. Checking in when changing sectors and trying to obtain IFR clearances at rural airports is slower and more cumbersome these days. I suspect this is due to reduced staffing at various facilities during the COVID-19 pandemic. This reduced staffing does increase the potential for reduced safety of flight; in my opinion.
Captain reported ATC issued a climb 2;000 feet above the filed altitude; crew took the altitude and did not question ATC.  Another Center Sector Controller eventually asked crew why they were going to newly assigned altitude instead of filed altitude.