Business Travel but Tourist Visa

My employer will send me and my other collegues to PRC for a business trip to support the subsidiary company in the project. Unfortunately the HR from PRC business M type apply now is much difficult and complex than before. Business M types do not allowed more than one month and no more extension in all provinces of PRC so they suggest us to apply tourist L type or apply work permit but we already had 5 expat in one of the province in PRC. So my boss decided we can only choose tourist L types. My concern is we will go to PRC back and forth to finish the project but what if the immigration notice this and ask why we always go back to PRC. Is this too risky?