P8 Fast Charge

Hi All:o Please can someone help? Two days ago I plugged my Standard OEM charger to my P8, the Lock screen came alive with a Yes or No, (I think), Fast Charge Option, I chose fast charge whereby the lock screen displayed three icons, fast charge, trickle and normal, (I think) respectively, charging seemed to go through those three stages until charged, the thing is that I can't find a fast charge option, I've looked on the Net but found fast charge is available but needs a Fast Charger to work so I tried my fast charger for my note 4 but still No Option came available. Was this a fluke or am I missing the trick here:confused:
Many Thanks in Advance and Kind Regards:)