I do not recommend that. The Purdy method is an excellent rule of thumb to measure the difference in development. But the weight this has compared to other factors, depends very much on the situation on the board.
As a general rule it can be said that development and activity have most relevance in open positions. In closed positions where the pawn structure is the dominating factor development is less important. This rule is illustrated in the graph below.
I will give two positions to illustrate this rule. The first position is taken from the Danish gambit. White has a deficit of two pawns, and a plus of three tempi (two moves to finish development, black 5). According to Point Count Chess, black should have a advantage, yet current theory gives the position as clearly better for white.
In the next position white also needs two more moves to complete development and black five. Material is even, and despite the advantage in development white has, theory gives this position as approximately even.
The difference between these two position is, that in the first position there is no heavy pawn structure. For this reason three tempi make up for more than two pawns. In the second position it is all about pawn structure, causing the difference in development to have no significance for the evaluation of the position.