10. WorldCom also claims that Verizon has overstated its switching costs by using an inappropriate switch vendor discount. The New Jersey Board directed Verizon to compute its switching costs as if 79.4 percent of the switches would receive the discount for purchases of new switches and 20.6 percent would receive the discount for purchases of growth switches. The Commission concludes that this issue is a fact-specific inquiry amenable in the first instance to determination by the state commissions; it is not a bright-line rule. The Commission has been presented with no evidence or rationale, beyond bare assertions, that would persuade us that the split chosen by the New Jersey Board amounts to a TELRIC error. It is satisfied that the New Jersey Board carefully evaluated this issue, properly rejected Verizon's proposed use of 100 percent growth switches, and validly established what it considered to be more appropriate and state-specific switching discounts.