I am happy to know that UPS will deliver my iMac 5K earlier than indicated on apple.com, but I will be at work Friday morning. Can I ask them to deliver for in the afternoon? I don't want to pre-sign it and let them leave at door... It's too expensive a machine so I don't want to take the risk... I will much appreciate it if anyone can tell me how to specify the delivery time.... thank you so much!