1. Why with the Yaz contraceptive pills there is 4 inactive pills but with other pills (levied ed) there are 7 inactive pills

2. I switched to yaz not long ago and it usually takes about 3 inactive pill days for my period to start which means i only have 2 days of my period. Im currently on my period now and today is my 3rd inactive day and i got my period. is 2 days enough for my period ?? When i was on levlen i had it for around 5 days cause it was 7 inactive pills? Is it okay to only bleed for two days? i feel as though thats not a very long amount of time.