Best way to model this data?

I have a table that i merged that has the following information

employee no

start date

end date

From the above i need to calculate the following

1. No of employees at a point in time down to day level

2. no of leavers

3. no of Joiners

4. Average no of employees by day

5. staff turnover

 For these measures i currently have the following table from my original table

Daily Aggregate = SUMMARIZECOLUMNS('Date'[Year], 'Date'[Month], 'Date'[Month Number], 'Date'[Date], 'Date'[Days of Month], "No Of Employees", CALCULATE(DISTINCTCOUNT('Employees All Time'[Employee No.]),
filter(
all('Date'[Date]),
'Date'[Date] <= MAX('Date'[Date])
)), "Leavers", CALCULATE(DISTINCTCOUNT('Employees All Time'[Employee No.]),
USERELATIONSHIP('Employees All Time'[Leaving Date],'Date'[Date])),
"Joiners" , CALCULATE(DISTINCTCOUNT('Employees All Time'[Employee No.]), USERELATIONSHIP('Employees All Time'[Start Date],'Date'[Date])))

and then created these off it it

Average Employee Count = CALCULATE(DIVIDE(sum('Daily Aggregate'[ Employees]),max('Date'[Days of Month])))

Staff Turnover = CALCULATE(divide(sum('Daily Aggregate'[Leavers]),[Average Employee Count]))

I was just wondering if this is the best way to do it?  The thing i struggled was creating the average, so i created a record for each day to get the average per month.  Just wondering if any one has a better way to do this.  Its also not very dynamic, for example if i wanted to get an average per week,  quarter etc...