No it's not- the cost of going from Y to MCS and then MCS to F on same-day upgrade is identical to the cost of going from Y to F.

http://virginamerica.custhelp.com/cg...p_sp=undefined

Main Cabin to First Class

* Long Haul Flights (such as New York to San Francisco) – $270
* Medium Haul Flights (such as Los Angeles to Seattle) – $110
* Short Haul Flights (such as San Francisco to Las Vegas) – $70

Main Cabin Select to First Class

* Long Haul Flights (such as New York to San Francisco) – $160
* Medium Haul Flights (such as Los Angeles to Seattle) – $55
* Short Haul Flights (such as San Francisco to Las Vegas) – $35

http://virginamerica.custhelp.com/cg...p_sp=undefined

Main Cabin to Main Cabin Select

* Long Haul Flights (such as New York to San Francisco) – $110
* Medium Haul Flights (such as Los Angeles to Seattle) – $55
* Short Haul Flights (such as San Francisco to Las Vegas) – $35