OT: Power Supply question

[Claude Jones]

I know this is off topic, but I appeal to the collective grace, and hope this 
list-fount of knowledge can answer or provide me with leads:

I just bought a new laptop which arrived yesterday. My previous laptop is an 
HP ZX5000 which had a P4 3GHz processor, and  took an enormous 120 W power 
supply rated to deliver 18.5 V and 6.5  A.

My new laptop is an Asus 'Gaming laptop' G2S-B2 (I'm not a gamer but I wanted 
this for its power which I use for video editing); the power supply states 
that it delivers 19 V and 6.32 A. It doesn't have a wattage output imprinted, 
but in the spec sheet for my new machine, it states that it requires 90 W

I noticed the closeness in specs, and tried one of the HP laptop power 
supplies on the new machine. It operates it just fine. My question is, am I 
liable to cause any issues by using a 18.5 V power supply in place of the 19 
V one. This of concern to me, because I keep three power supplies on hand for 
my machine, two of which are permanently installed at my place of work and in 
my residence, and the third which is for on-the-road use. It would be nice if 
I could get away with using my spare HP units and not have to buy two more 
power supplies for my new machine.
-- 
Claude Jones
Brunswick, MD, USA