Potting on seedlings

I have a whole load of trays of seedlings (Delpheniums, Lupins, Hollyhocks, Verbascium etc. etc.).  I now need to pot them on and bought a big bag of Potting Compost (John Innes).  I potted on the first of them this morning but stopped because the Potting Compost seemed to be wrong!!  I was expecting it to be loose but t is very dense and when I press it into the pots it seems to compact and I am afraid that it will deprive the plants of air - does anyone know if this is ok?  Should I mix ordinary compost, vermiculite or something like that or should I just forget about it altogether and just pot them on into multi purpose (I have 3 big bags of that - compost heap only new so no homegrown stuff yet).

Thanks folks, fluffed up the compost as suggested and did some more potting on last night, I was just careful to firm them in but not to press really hard so that it was too compacted - they all look very happy this morning.  Now my next problem is what to do with 100 verbascum, 50 Lupin and 50 delphinium.