Electric vehicles (EVs) are becoming an important part of the power system, offering flexibility for grid support through frequency regulation services. Frequency regulation markets rely on resources to balance supply and demand in real time, making EVs a promising asset for grid support services. This study examines the most profitable way to operate EV chargers in a parking lot of an electrified office building powered by a building-integrated photovoltaics (PV) system. The model schedules the charging and discharging of 22 EVs, assuming a single building operator participates in both the dayahead electricity market and the manual frequency restoration reserve (mFRR) balancing market. The model inputs are the EV mobility patterns, historical PV generation, building load profiles, and market price data for 2024. The results show that mFRR energy activation market (mFRR-EAM) prices are irregularly concentrated in a small number of high-value activation hours, whereas mFRR capacity market (mFRR-CM) prices follow a more stable and predictable seasonal pattern. Furthermore, smart charging reduces annual costs by up to 1.40 k € compared to uncontrolled charging, and V2G operation improves local PV utilization and reduces network peak demand. Participation in the mFRR market yields additional savings of 0.17k€, with limited impact on battery degradation. The study provides practical insight into the economic value of smart EV charging at commercial workplaces with co-located PV generation.