Understanding different animation blends

Hi. I’ve just started looking at converting to Unreal from Unity. I have good software skills but I know very little about animation.

To experiment, I was looking at the free asset ‘Fighter F/A-18C Hornet (West)’ by Vigilante. The example level they provide doesn’t have a correct animation of the undercarriage. The wheels and undercarriage doors all animate at the same time and pass through each other. They have provided individual animations of each wheel and these work OK in the animation editor showing a correct sequence of wheels closing first and the doors closing afterwards.

But when the project is run, the wheels and doors all animate at the same time due to a ApplyAdditive node being used in the animGraph. My understanding is this node is controlled by a float value 0.0 to 1.0 and all bones move at the same rate from the start position to the end position rather than follow the animation sequence itself.

How can I get a blend node (or something else) to follow an animation sequence exactly and not a partial blend of the animation sequence and base pose? All the tutorials I have looked at are humanoid animations where blending works well for humanoids but not for aircraft animations.