Hi and welcome to Globe...
You actually availed of a Plan 999 of which the cost of your subscription is Php 999.00/month BUT with a supposed value of P1,700 of which they call Peso Value or PVs.
The PV of 1700 is applied to the cost of Combos (in which case you got unlimited data worth Php999/month) and a gadget (in your case the Nokia lumia 1320 costing xxx/month). Your remaining PV would be 1700 less 999 less the PV value of your gadget (xxx) of which you can apply for other Combos or consumables (calls, sms, mms).
Boosters are charged on top of your monthly subscription and are not included in the calculation of the PVs.