When a district court grants a downward departure, however, it must do so based primarily on factors related to the defendant's substantial assistance. See Grant, 636 F.3d at 817; United States v. Verburg, 588 F. App'x 434, 444 (6th Cir. 2014). Given that comparatively limited discretion, an error a district court makes when calculating or imposing a departure is less likely to be harmless.
As to his sentencing memorandum for resentencing, "a sentencing memorandum—written and submitted before one's sentencing hearing—cannot be considered a suitable way to preserve an objection to actions taken at one's sentencing hearing." United States v. Verburg, 588 F. App'x 434, 444 (6th Cir. 2014) (citing United States v. Vonner, 516 F.3d 382, 385-86 (6th Cir. 2008) (en banc); see also United States v. Mizori, 601 F. App'x 425, 431 (6th Cir. 2015); United States v. Lamb, 431 F. App'x 421, 424 (6th Cir. 2011). Thus, plain error is still appropriate.