P3112 Date calculation with queue hours on identical work centers

I am trying to figure out how the date calculation works in manufacturing. So far, when no queue hours are defined it works as expected and what I can find in the documents about calculation dates. But when I define queue hours on the routing steps, I cannot explain the dates calculated anymore.

Item A - MFG leadtime quantity 48

Four routing steps:

OPSQ	WC	Queue	Setup	Mach	Labor	Move
1	w103	1	2
2	w173	4	1	2
3	w152	4	1	6
4	w152	4	1	6

Three work orders:

WO	Item No	Qty	UoM	Start Date	Request Date
195062	205.837.001	60	EA	17-2-2014	21-2-2014
195938	205.837.001	48	EA	18-2-2014	21-2-2014
195939	205.837.001	24	EA	18-2-2014	21-2-2014