The scenarios are described in Scenarios on WBS Quantities or Other Fields.
The main estimate passes on to child estimates the sub-set of scenarios which applies to them.
If the main bidder has locked certain WBS quantities of the main estimate, the sub-contractor cannot edit them. QDV7 shows a report when the child estimate is fed back into the main one.
A sub-contractor can add its own scenarios. However, they will not change the main scenarios table on feedback.