You do not get an additional 40 Lifetime subs, any people in the group that are getting passes come from that total. If there are left overs, then those can be distributed. This is unlikely, but possible. Example:
If 10,000 people each donate 1 dollar, then you reach $10,000. 40 passes have to then be shared with 10,000 people (only 40 will get one).
More likely, if 40 people put in $250.00 each, they each earned a pass at the $250 level, which means that they used up 40 passes, and there are no extra passes for the 'Leader' to distribute.
It is the other 'In-Game' type rewards that will need to get distributed in most cases.
It's meant so that you still get your rewards, but you can also achieve higher tiers as a group.