No, The network claims to have the potential to route traffic via ISLs to create a space path for international traffic at some time in the future when all satellites are equipped with ISLs, preferably laser links. Currently, only a few "test satellites" are quipped like this covering the polar regions because it is those areas that have no alternatives and are not likely to be supported by very large GS networks. The efficiencies are supposedly going to come from very large capacity laser link ISLs. The "switching time" between satellites (especially under loaded conditions), not known.
The will depend on the number of satellites covering the area where you are and the impact again when the network becomes heavily loaded is unknown at this stage. There obviously will be handover issues every time a new satellite takes over your connection.
From microseconds to minutes.
While this is great in theory, what I meant is from someone actually testing it. And yes, as you pointed out, more specifically once it has tested under loaded conditions. I remember when I did a beta test for Web Africa's new network years ago and was amazed about the 155 ping they offered on ADSL. Then the service went live and it shot up to 170/180. Still good at the time, but not what I was hoping for.