showing this. Typical complicating factors that make an employer's status ambiguous include the extensive use of part-time workers, existence of multiple entities that need to be grouped as a "single employer", and significant employee churn. Public access file The U.S. Department of Labor does not require all petitions to be in the public access file, but it does require the public access file to contain the list of all exempt nonimmigrants. However, if all petitions filed by the employer are for exempt nonimmigrants, then this list need not be maintained. Additional documentation of employee lists and payroll, that was used to determine H-1B-dependency, should be maintained by the employer, but does not need to be part of the public access file. Additional fees H-1B-dependence itself does not trigger any additional fees. However, at various points in the history of H-1B law, additional fees have been levied on employers satisfying conditions similar to H-1B-dependency. These are employers who have more than 50 full-time employee equivalents and with the number of H-1B and L-1 nonimmigrants at present equal to more than 50% of their current number of FTE equivalents. The corresponding threshold for H-1B-dependency is 15%, but one way these thresholds differ is that the 50% threshold for the additional fees requires the employer to count people in H-1B as well as people in L-1 status. Also, unlike the case of additional LCA attestations, there is no exemption for people based on how much they are earning or their educational qualifications. Whereas the concept of H-1B-dependence is used only by the United States Department of Labor, the extra fees here are levied by the United States Citizenship and Immigration Services. Public Law 111-230 (August 2010 to September 2015): additional fee of $2000 Section 402 of Public Law 111–230, signed by then-United States President Barack Obama on August 13, 2010, imposed an additional fee of $2,000 on certain H-1B nonimmigrant petitions and $2,250 on certain L-1A and L-1B petitions. All the petitions involved are filed using Form I-129, and these fees apply over and above any applicable fees for those forms. As mentioned above, an employer was required to pay the additional H-1B fees only in the case that the employer had 51 or more employees and H-1B and L-1 employees together comprised over 50% of the workforce. The fee would apply only to petitions on postmarked on or after August 14, 2010,