Why setting some value to vm.dirty_bytes resets vm.dirty_ratio to 0?

Issue

• Why setting some value to vm.dirty_bytes resets vm.dirty_ratio to 0? (or vice versa)
• Why setting some value to vm.dirty_background_bytes resets vm.dirty_background_ratio to 0? (or vice versa)
• Why setting vm.dirty_ratio and vm.dirty_bytes in sysctl.conf sets only one of the values? (same for respective background parameters)
• Why setting vm.dirty_background_ratio to 0 after vm.dirty_background_bytes in sysctl.conf resets the value of vm.dirty_background_bytes to 0?