Fewer sales doesn't mean a decreasing average, or have any effect on average other than making it more volatile.
You may want to check you math on that. Assume:
August:
3 McMansions sell for $1,000,000 => $3,000,000
70 Townhomes sell for $100,000 => $7,000,000
Therefore, 73 homes have an average selling price of $137,000
September:
2 McMansions sell 1,050,000 => $2,010,000
73 Townhomes sell for $105,000 = >7,665,000
Therefore, 75 homes have an average selling price of $129,000
With those results, which headline might you see in the MSM?
A. "Home values rise by 5%!"
B. "Homes sales increase by 2.7%!"
or
C. "Home prices in "Free-Fall"! -- DOWN 6.2% in one month!"
Hmmmm...
"Lies, d@#m lies and statistics"...