Statistics of an SMA

My Fidelity advisor had suggested moving some money to an SMA after I kept complaining about non-trivial long term capital gain and qualified dividends I was getting, ousting me closer to an IIRMA threshold. I did, and yeah, it's the 200 stocks he said I'd see, since it tries to mimic a Large Cap Index fund, but with tax-harvesting benefits. My question is how I might evaluate its performance? Individual funds provide a long term performance graph under "All Accounts"/"Positions", but the SMA does not. So is all that's left is to watch the "Account Total" line's "Total Gain/Loss" and "%Total Gain/Loss" ? Wouldn't that quickly get undermined if I buy more or sell some? Is the only accurate way to record "Account Total" -> "Current Value" on dates that any transactions occur, and code up a simple algorithm to compute "performance"? The goal is to compare to the Fidelity U.S. Large Cap Index (actual fund name?) and see if the 0.4% fee is worth it. Thanks for any insight.