This study aims to determine the Application of Differential Costs in Decision Making to rent or buy fixed assets (musical instruments) in the field of musical instrument rental. This type of research is quantitative research. Data is obtained through primary and secondary data. This research was conducted in 2020 to 2022. Data collection techniques through interviews and documentation. Data analysis techniques are carried out by identifying data on interview costs, observations and documentation at the New Arista Orchestra. Based on the results of the analysis, these relevant costs can be used as considerations for the company in making decisions. With the alternative of buying, it will save costs of IDR 76,257,322.93 or 2.7% in making decisions with the alternative of buying or renting heavy equipment, it is better to consider the expenses that will be incurred from the two alternatives with relevant costs so that the decisions taken can benefit the company. The results of the comparison using the differential costs above. it can be concluded that differential cost analysis is very useful for the new Orchestra in making better decisions taken by the orchestra is to buy because it is more profitable than renting musical instruments.

The government passed Law on Harmonization of Tax Regulations no. 7 of 2021 In an effort to restore economic stability after the pandemic. In this provision, there are six changes regulated, one of which is regarding changes to the income tax rate in article 21. These changes in rates have been adjusted to reflect the conditions of society when facing the Covid-19 pandemic. The aim of this research is to analyze changes before and after the implementation of the Law on Harmonization of Tax Regulations in all Pizza Hut Branches in Kediri City. The method used in this research is descriptive quantitative with data collection techniques through observation and interviews. The results of the research show that the Take Home Pay of employees at Pizza Hut Restaurant according to the Law on Harmonization of Tax Regulations is IDR 154,555,773 and according to the Income Tax Law it is IDR 154,015,439. Meanwhile, at Pizza Hut Delivery Branch 2, the total employee take home pay according to the Law on Harmonization of Tax Regulations is IDR 119,712,095 and according to the Income Tax Law it is IDR 119,374,160. Take Home Pay for permanent employees with PKP below IDR 50,000,000 does not change because it is still within one layer of the tax rate. It is hoped that this research can contribute to companies in optimizing employee income tax calculations so that they can increase employee take home pay.