i plan to invest $100 weekly for 5 years ($26,000 total) to average market entry.
Op I think you are getting yourself confused,
Weekly investment you said : $100
Total for a month investment: $100× 4weeks = $400
And I think your yearly should be : $400 × 12 months = $4,800
In your previous calculations it seems you had an error, just like you said investing $100 per week would indeed result to a yearly investment of $4,800 and not 26,000 so take corrections of that.
You are the one that is confused and you have to correct your calculation by going back to check how many weeks we have in a year. I believed you are eager to correct when you have not checked it very well.
Even though we have 4 weeks a month, you don't have to calculate it like that because even though we have 4 weeks in a month, there is always a remaining day out of every month except February.
Okay let's do the mathematics here;
4 weeks makes a month with exception of 2 to 3 days.
Only February has 28 days to complete a full month
365/366 days(leap years) makes a year. If you divide 365 days by 7 days it will be 52.
Which means 52 weeks make a year.
52 × $100 = $5,200 per year
Since he said he would be investing $100 for a period of 5 years.
$5,200 × 5 years = $26,000
This means he would be investing $26,000 for a period of 5 years at an interval of $100 per week.
This is a typical DCA strategy, buying Bitcoin at different price range which is highly rewarding if he's holding for a long period of time.
The confusion here lies in the fact that financially, a week is 7 days from the day you make your first payment or deposit. It is not tied to the names of the days or the conventional calendar. Only 7-day intervals are counted from the moment it begins, although the mathematically correct thing to do would be to express it in days, not weeks or years. This confusion comes from the banks, because they do this to create a situation of false stability. For example, if a person is paid on Fridays, by telling them they will be paid weekly, they may assume that their payment will always occur after receiving their salary. However, there will be months in which the 7-day cycle causes the payment to be anticipated, creating unexpected financial pressure.
I would dare to say that most people get confused about this. What the centralized system has done to us.