Why are the response time and content length different among different locations for the same time period in my Web Page Speed (Browser)?
Site24x7 resolves a domain by connecting the website and downloading the complete HTML source of the webpage. The content length will be captured based on the response given by the target server. Also, each object available on your page takes different time to load from different monitoring locations, which results in the different response value when compared with the configured locations.
In Web Page Speed (Browser), we will send HTTP/HTTPS requests to each object available on a page to monitor its availability and performance.
You may also notice a variation in the actual size of the content with the monitored content (The monitored size is 400B, whereas the actual size of the page is 4MB). The content length shown on your monitor is only the size of HTML source downloaded. Hence, the size is different when it's compared to the actual web contents (i.e, including images, scripts, etc.).
To gather a quick comparison of various website monitoring features, refer this comparison sheet