Edit: Apparently they do track daily cap hits it's just a premium feature.
Because they don't actually track daily cap accruals and treat everything as if it's for the whole year.
for example the NHL season is 192 days this year (IIRC)
Rantanen doesn't cost 4.625m against Chicago, nor does he cost 4.625m against Dallas.
It's more like 6.26m to Colorado (based on number of days on Colorado Roster I estimated the number of days around 130)
1.49 to Chicago (50% of the remaining for 62 days)
602k to Carolina
888k to Dallas
is a rough estimate of how the cap hits break down just for Rantanen.
Now take someone like Bichsel
his cap hit is 918k for the whole year.
But he didn't and won't spend the whole year on the roster.
to further the point, the Stars did a lot of paper transactions with him this year, where he would spend close of business day on the AHL roster, so the stars would avoid his cap hit.
so you take his 918,333 / 192 = 4783 per day on the NHL roster.
But what they were doing with him for much of the year
is
Monday = Game day =on the nhl roster (+$4783)
Tuesday = No game (He's "sent" to the AHL) so no cap hit tuesday
Wednesday = Game Day = back on the nhl roster for close of business (+$4783)
So of the 192 days in the NHL season, he's spent/will spend maybe 60-70 days total on the NHL roster to count against the cap.
So his actual applied cap hit for the year will be 286,980 to 334,810 against the cap. Maybe more depending on the actual number of days, but a fraction of the 918k.
But if you were to check Puckpedia or capwages he counts as if it's the whole 918,333.
It would take a lot more resources than most of those sites have to accurately track that information, and generalization is good enough for the average person's usage, but they aren't actually accurate