Well assuming that Phillips know what they are doing then it should be OK on the two screws, however you can to something to make sure it is as secure as possible - such as use only round head screws not countersunk to fix it, and make sure that you chooose a screw size where the head is a exact fit in the large part of the holes, if you use screws with heads large enough to be a bit tight and difficult to get through the holes then they will also be difficult for it to fall off if knocked.
Last but not least use the correct size wallplug and drill for the screws which you use and use pretty long ones if you can. After you put the wallplugs in the holes use a punch to push them slighty into the wall so that they don't bulge out when you put the screw in otherwise the TV will not be completley flat to the wall.