I regularly use abs for small scale production as you What has become clear to me is that all abs filaments are not Equal. The filament we have found best is ABS-X made by Mitsubishi Chemicals in Holland (MCPP)but is only sold as own brand filament the one we purchase is 3dFilaprint ABS-x but in UK Ooznest also sell the same material as ABS-plus. The manufacturer recommends 240 to 260C for printing I have used it down to 235C. I print at 70mm/s. bed at 80C.

About your blockage it can occur because the tube which feeds the filament to the heater zone is not firmly against the nozzzle and leaking melted filament which hardens and causes a blockage.