In this section, “depreciation” means a reduction in value due to wear, tear, decay, corrosion, or gradual obsolescence of a fixed asset having a useful life of more than 1 year. A trustee may transfer to principal a reasonable amount of the net cash receipts from a principal asset that is subject to depreciation, but may not transfer any amount for depreciation: Of that portion of real property used or available for use by a beneficiary as a residence or of tangible personal property held or made available for the personal use or enjoyment of a beneficiary; During the administration of a decedent’s estate; or Under this section if the trustee is accounting under § 15-510 of this subtitle for the business or activity in which the asset is used. An amount transferred to principal need not be held as a separate fund.