In these posts - arm_up or arms_up?

Each of these drawn girls has one hand far up, the other hand is around eye level.

The wiki of both tags mention that "being aroung eye level" counts as "up", so apparently all these images are supposed to be arms_up, not arm_up. Is that correct?

• post #838164
• post #948915
• post #1029442
• post #1026047
• post #765965
• post #1049938
• post #1049257
• post #1038789

The list above is currently balanced, on purpose: 4 arm_up images and 4 arms_up images.

All of them are arms_up. Just ignore their forearms and hands for a second and look at their upper arms' angle.
An arm_behind_head is always an arm_up, or arms_up depending on the other arms position. (Maybe arms_behind_head could implicate arms_up)