I’m only a customer and AxCrypt’s support may be along to provide further information. You could always email them and see if they can accommodate your requirements.
What I will say is that if you’re using BitLocker then there’s no need for third-party solutions for data at rest, whether it be AxCrypt or Sophos.
Most third-party software leverages BitLocker in any event. You really don’t want to start “double encrypting” things because the potential for data loss increases.
I don’t understand what you hope to achieve by using two layers of encryption – it doesn’t make your data any more secure when at rest. If you want to share files outside your organisation then AxCrypt is ideal. Sophos is extravagantly expensive and if you’re never sharing files externally then it’s totally unnecessary.
Microsoft have many DLP solutions if that’s your concern. I’m interested to know what you believe the benefit to be by using two layers of encryption?