Re: Why not ask SpaceX?
Well I believe that the normal approach will be to launch the sats in groups of 4 on Ariane 5 (which has an excellent record for very precise orbits). However, they wanted to launch fewer for the first launch to test out the design of the satellite to allow the following satellites to be modified if required. Hopefully, the booked Ariane launches will go without a hitch. Note that SpaceX has also failed to deliver 2 payloads to their correct orbits.
Also the European union /ESA probably would prefer to use Ariane because it helps to assure European access to space (Ariane was originally developed because the US said that Europeans could launch sats on their rockets, but would not be allowed to keep any money made by the satellites - imagine how the telecoms market would look in that case). This may be seen as similar to SpaceX receiving a large amount of cash so that the US can launch cargo/people to the ISS without using Russian launchers, or satellite manufacturers in the US being banned from using launches provided by the Chinese.
Biting the hand that feeds IT
