You only truly know the return from an Investment after you sell it. 

Until then, any measure of return is based on a current Valuation, which may be difficult to determine with certainty, and which may also not take into account liquidity and all costs associated with a sale.

In addition, TWR and MWR are annualized so for any very recent investment these metrics may not be very meaningful, especially when there is volatility. For example, a drop in value of 2% during the first week of ownership of an asset would translate in an annualized MWR of -60%: although technically correct, this number is somewhat misleading given the short period of performance observation.