it does not sound to good...did you notice any air bubbling in the expansion tank? You should have not had any rise in the expansion tank when you first started the car, and you should have had %100 less pressure...what do you mean by you had %70 less?? So your saying...you still had pressure?
If so....sounds like it could be a gasket leak, or cracked head. Before you go any further...why don't you take a shot at back flushing the cooling system with one of the hoses removed and the thermostat removed...see if you dislodge any debris. Or pressure test the rad system, with a pressure tester to confirm a head gasket leak.
