An investment firm has a portfolio consisting of three stocks: Stock X$,$ Stock Y$,$ and Stock Z$.$ The firm invested $$50,000$ in Stock X$,$ $$30,000$ in Stock Y$,$ and $$20,000$ in Stock Z$.$ Over a year, the returns on these stocks were $8\%,10\%$ and $12\%$ respectively. Calculate the weighted average return for the portfolio and interpret the results in terms of the firm$$s investment performance.