Can you continue to take same dosage?

I take a vitamin b12 that is 2500mcg. The dosage is take one daily. I just went to pick up another bottle and the highest dosage I found is the 500mcg. The dosage on this bottle is to take up to 3 daily, which would equal 1500mcg, 1000 less than I have been taking. Is it okay to take 5 of the 500mcg even though the directions say take 3 daily, since I have been taking a 2500mcg one daily. Thanks