The projected SLG is definitely wrong; it will stick out like a sore thumb when you are drafting a team.
Using one of my drafted teams, the calculation appears to have taken into account the 60 game 2020 season and the 154 game schedule prior to 1961 for many of the hitting variables. However, there are some that are close but definitely off (e.g., CS). Also, not sure if the assumption of games is always the same amount per team per season (how does it deal with rainouts, games that were suspended without a winner and replayed, playoff game(s) to decide the pennant, etc...). These are small differences, but do they get taken into account?
Obviously it is AVG & OAV for the 70M theme and HR/9 for the variable cap that need to be correct. They look to be fine, but others should check against their team(s) as well...