Help finasteride 5mg question.

[aznapplejuice]

So i recently got some finasteride from my dermatologist. He told me to cut them into pieces of 4 which end up to 1.25mg each. But i'm scared of sides so I am going to start out with .5mg

Heres my real concern. I bought a scale that can measure milligram. Its called Gemini-20, got it off amazon. It convert grams into milligram. So I put the pill on the scale in it measured to 0.120 GRAMS which is 120 MILLIGRAM... LIKE WHAT!? i cut it into 4 pieces which came up to 30mg X.X

i went to my pharmacy and she told me that its probably because there other active ingredient in there. It's not only finasteride alone, but other component that contribute to its weight? So is it true? then how the HECK do i measure this?

I am assuming 120mg(5 mg fin)/4 = 30mg (1.25mg fin) AND 30mg/2 = 15mg (0.625 fin)?

HELP~ i want to start fin ASAP. already got my testosterone checked and im mentally prepared.

(this is the scale and how i measured it) 0.001 = 1 mg
http://aznapplejuices.imgur.com/all/?third_party=1