The Small Business Administration’s Paycheck Protection Program, which many small law firms had hoped to use as a lifeline to avoid furloughs and other cuts, burned through its initial budget of $350 billion in loan guarantees in barely two weeks.

While the Senate voted on Tuesday to add at least $310 billion to the program, some lawyers at small and midsize firms are already frustrated with the process, expressing concern with how the government or the banks handled their application.