Motorola advices you to charge the phone to full initially, and there are folks who say this is important, but the critical thing is to drain it completely initially, and then to do so again every once in a while (every month-ish). The battery's internal gauge needs to be show where the bottom and top of the battery are. Draining it shows the bottom, and filling it shows the top. The reason we don't need to worry about the top is because almost everyone charges their phone to full on a regular basis, but draining is far more rare. Draining your battery frequently will shorten its life, so don't do that.
As time goes by, the gauge gets less accurate, which is why it is good to drain the battery again now and then.
So top if off now or later, neither will hurt you, just remember to drain it at your first opportunity. Don't put too much faith in your battery readings until you do both.
