Periodic Mass Copy does not bring over Adjustments in previous Month

Hello

Example before I quote my question;

CORP BOOK:

FEB-16         ADJUSTMENT    Cost=1000

JAN-16         ADJUSTMENT    Cost=900

DEC-15        ADDITION           Cost = 800

TAX BOOK in JAN-16:

JAN-16(transaction date)         ADJUSTMENT    Cost=900

DEC-15        ADDITION           Cost = 800

We ran Depreciation for JAN 16

Same lines;

JAN-16         ADJUSTMENT    Cost=900

DEC-15        ADDITION           Cost = 800

After Periodic Mass Copy for FEB-16

Tax Book Shows:

FEB-16         ADJUSTMENT    Cost=1000-------New Adjustments for FEB got copied over

DEC-15        ADDITION           Cost = 900-------Adjustment for JAN did not come over as Adjustments but as Addition per transaction date = Date placed in Service(DPIS).

Q: I do not understand why the Adjustments did not come over for JAN and why it came over as an Addition for a transaction date of DPIS (Period entered is correct JAN-16)?