they say 10 individual movments a day even if there all at the same time, But i would go by the babys pattern more than anything, say ur LO is more active normaly on a night but you dont feel much movement, have a drink of cold water ect its possible they could be having a lazy day, I normaly worry if he's been quiet for more than 24 hours which is unusual, its only happend once. If your worryed about the babys movements tho go see the the midwife they honestly dont mind they'll strap you up too a monitor and baby will probably start dancing away as soon as you get there but they'd rarther people went in if they were worryed than stay at home.
I told her i felt a bit silly for going in last time he hadnt moved much for about 48 hours, he had a little but not as much as usual as soon as i got there he was jumping around all over she said not too worry about it and always come in no matter what if im worryed x