Hello all. I have a late 2008 MPB with a 85W Power Adapter. My other half has a 2009 Macbook pro with a 60W Adapter. These laptops are about 6 months apart, why the difference in adapter? My BFs 60W recently packed up working (the rabbit nibbled it) so he's been using my 85W. Is this safe for his laptop? I've use to use his now and then, as I never noticed they were different. Was that safe? Many thanks. We both have 15" btw.