FA_INV_XFR_PUB.do_transfer - What's wrong?

I'm trying to use API procedure "FA_INV_XFR_PUB.do_transfer" but I can't find out the correct value for parameter "l_inv_rec.fixed_assets_cost".

On Asset User Guide we can see the following description: "This is the delta amount for each line you wish to transfer. It must be between 0 and the current cost of the line in question.". So, I put the current cost of asset in parameter but I got errors from API.

What I supose to do?

My code:

declare

  -- source

  l_src_trans_rec             FA_API_TYPES.trans_rec_type;

  l_src_asset_hdr_rec         FA_API_TYPES.asset_hdr_rec_type;