NGC 2516 is somewhat richer and more massive than the Pleiades. A careful look at the mass function suggests there is about $1000 M_{\odot}$ in stars $\geq 0.3 M_{\odot}$, within the central 0.9 square degrees (with about a 15% uncertainty), but there is probably a few hundred solar masses beyond this (Jeffries et al. 2001). This agrees with the figures of Dachs & Kabus (1989), who essentially extrapolated from the numbers of high-mass stars using a typical cluster mass function.
New Gaia data will probably provide a more complete census in the halo of the cluster. There will also be some additional mass in lower mass stars and brown dwarfs, but this is unlikely to add more than 10% to the figure.
The lower masses quoted in your question are way too low. In an incomplete spectroscopic survey of the central square degree, a recent paper by Jackson et al. (2020) found about 500 low-mass members ($0.4-1.2M_\odot$), that alone would add up to about $400 M_\odot$, before considering the many high-mass stars.