Items reservation at the time of booking or pick release?

 Hello Experts,

We can reserve quantity at the time of sales order booking  or at the time of pick release.Let suppose the setup is at the time of pick release.But our sales order Booker's are facing problem at the time of booking.

Assume we have 10 quantities for ABC item.There are many user for booking the same item.One customer order for ABC item ,he check the on hand quantity on sales order and booked.The same item ordered from other customer and the 2nd user check the on hand quantity,It is showing still 10 quantity on hand and he also booked the order.In these case user booking only order without pick release and misguiding the customer that they have enough quantity available in stock while the quantity is already booked.