Finest Detail only affects the amount of data accepted for input and not the output resolution. The rastered image will favour sharper lines to support text or other vector images, but the output resolution remains unchanged.
Overall, the variation in total ink usage between all the printing modes (excluding 360 or draft output modes) is very small and would not likely be the cause of this problem. The damper allows sufficient reservoir of ink to be held to guard against quite reasonable air bubbles without interuption to printing, so a minor starvation issue (such that it doesn't cause an error due to pressure failure) seems unlikely to consistently cause failure after a certain time/length.
Regarding the banding versus print length, the displayed sample is too small to determine that the banding is consistent or 1:1 as Bernard is printing over a considerable length with the panos.
Concerning the ink starvation issue, I also doubt this is the case as such a starvation would result in nozzles firing empty which would be detected by the AID as a blockage, but Bernard is not reporting that the printer is indicating any nozzle blocks or attempting to clean and, indeed, if the printer did do into an extensive cleaning cycle then the time taken would allow for the pump to "catch up" in filling the dampers which would result in the starvation being fixed (and therefore starvation banding being eliminated after the cleans). Significant empty fires could also increase head temperature sufficiently to cause an error.
I still believe that a lengthy printing of C M Y and K strips will help to determine the nature of the problem, as will printing without Finest Detail and also checking at different output resolutions. It will also help to determine if it is a single channel or all channels and if it is all channels, then starvation can't be the problem or you would simply have fading prints rather than banding. If it is just one channel, then there is a possibility that the particular channel is the issue but since the banding appears consistent across various colours of the print, that doesn't appear to be the case.
At this point, though, regardless of the cause, a service technician is required, imho.