I am trying to create a Anchored VWAP for Trading view, but the problem is, it is not consistent when moving to a higher timeframe.

Trading View has a native drawing tool for Anchored Vwap, and it works consistently.

Example: If I plot my AVwap on the 14/April/2021 at 4am (4 hour chart) if I go up to a daily chart my AVwap will move to the 15th, but TV's AVwap Drawing tool works correctly at 14th. If I go to the weekly chart, my AVwap goes to the 19th, but native Drawing tool goes to the week 12th (which is correct).

What should I change in my code for it to work as the native drawing tool does?

This is my code:

 

Code

//@version=4 study("My Midas VWAP TimeStamp", shorttitle="MY MIDAS TS", overlay=true) showmidas01=input(true, title="Show Midas") startBar01 = input(timestamp('14 Apr 2021 04:00 -0400'), '#1 Start Time', type=input.time) mid01= true //input(true, title=" Show Midas 1 Line" ) startmidas01 = time >= startBar01 and time[1] < startBar01 v01 = na(volume) ? 1 : volume cumV01= cum(v01) CumPV01= cum(hl2*v01) startV01 = valuewhen(startmidas01, cumV01[1], 0) StartPV01 = valuewhen(startmidas01, CumPV01[1], 0) Midas01 = (CumPV01-StartPV01)/(cumV01-startV01) middle01 = plot(mid01 and showmidas01? Midas01:na, title="Midas 1", color=color.aqua,linewidth=2)

Your script identifies a specific point in time (timestamp) for the plot session to initiate. If a bar opens at the same time as your timestamp then the MIDAS/anchored VWAP will be initiated at the same time as your timestamp. If the bar does not open at the same time as your timestamp then the MIDAS/anchored VWAP will be initiated on the next bar open.
To compensate you should have the script query the timeframe and then initiate the MIDAS/anchored VWAP one bar earlier in time. If you move to a weekly chart the initiating time must be moved back in time by one week.
I have added a line to address your specific request. I have not coded in any exceptions, that is to say, what if the timestamp is exactly at the starting point of a daily and/or weekly bar. The script will still subtract the daily or weekly time equivalent, which is not what you want. You might well be able to address this particular exception by using the following line as an alternate to the one I inserted below: startBar01=timeframe.isweekly?startBar_01 - (1000*7*24*60*60)+ 1000:timeframe.isdaily?startBar_01 - (1000*24*60*60)+1000:startBar_01. I have not tested it.
Also, I changed the plot colour to navy so that you can see the different plots.

// foreverlearner with input by jayy

//@version=4
study("Midas anchored VWAP TimeStamp", shorttitle="MIDAS TS", overlay=true)

showmidas01=input(true, title="Show Midas")

startBar_01 = input(timestamp('14 Apr 2021 04:00 -0400'), '#1 Start Time', type=input.time)
mid01= true //input(true, title=" Show Midas 1 Line" )
startBar01=timeframe.isweekly?startBar_01 - (1000*7*24*60*60):timeframe.isdaily?startBar_01 - (1000*24*60*60):startBar_01
startmidas01 = time >= startBar01 and time[1] < startBar01

v01 = na(volume) ? 1 : volume
cumV01= cum(v01)
CumPV01= cum(hl2*v01)

startV01 = valuewhen(startmidas01, cumV01[1], 0)
StartPV01 = valuewhen(startmidas01, CumPV01[1], 0)

Midas01 = (CumPV01-StartPV01)/(cumV01-startV01)

middle01 = plot(mid01 and showmidas01? Midas01:na, title="Midas 1", color=color.navy,linewidth=2)