I seems obvious that Prestwick SAR took the incubators and staff to Stornoway because the twins were in too delicate a condition to be taken direct to Glasgow by the S-92 at Stornoway. Then the Herc was used to transport the team and twins based on a medical assessment of what was best for the patients - a shortish and not too bumpy ride in a C130 or a longer and much bumpier ride in an S-92, not a difficult decision really.
Good job all round with a good result.