You can change the portfolio net asset value when you first build/import a portfolio:
Everysk computes a forward looking distribution of profit and loss (PL) for the portfolio, in base currency. Setting the NAV will produce percent statistics proportional to the inputted NAV.
Leaving the NAV blank will force Everysk to compute it. That value might not coincide with the true NAV for various reasons, including the margining method applied to the portfolio.