DY Vul

Hello,

a newbie question about DY Vul: what does "p" magnitude code means? 

I ask this because the chart (8643KO) says  Magn. 8.4-9.7p , but my observations, and even the light curve from LPG, shows higher magnitudes than 8.4 so I wondered why. Maybe because these mags are not v ?

thanks

Massimo (BGMB)