I have an older model Ace250. This cuff has reinforced grooves which don't align with the rear mount, not a seamless fit, but will suffice. Seems that they have resolved a known issue of the cuff breaking.
The replacement part is reinforced with gussets, making it more durable than the original. Because of the gussets, the mounting screw could be slightly longer, but it did grab. Thanks for the great customer service, because I ordered It on a Friday after regular hours.