For real portfolios, the value chart number will likely differ slightly from the current portfolio value like the example below.
The value chart shows the growth of a certain dollar value invested in the portfolio over time. To show this, the value chart works by taking a starting point which is the current portfolio shares, as of the date of start. Since the price of each asset is likely different on the start date than it is today, the total value of the portfolio will differ at that point in time. See image below as an example.
The value chart then displays the end point which is the current portfolio shares, simulates from the date of start, and accumulating dividends. This may be end up a bit more than today's value.