“Skip offers” feature works like this:
Assuming that you have a funnel for product A with 2 upsells (and with “Skip offers” enabled):
- product B
- product C
When customer has product A only in his cart, funnel will work as usual: 2 upsells will be shown as you set them up.
Otherwise, when customer has product A and product B in his cart, the funnel will be shown, but upsell product B will be skipped, while upsell product C will be shown as usual.