Google Play - How to add yearly subscription plan to exsiting monthly subscription plan

Question

Ever since Google Play Billing Library 5 is introduced, a concept of based plan is introduced in Subscription.

A single subscription, can have multiple based plan. The based plan can be either charging monthly, or charging yearly.

Currently, we already have a legacy monthly subscription plan.

If we want to support yearly subscription plan, here is what we need to do.

1. "Add base plan" in existing subscription plan.
2. Use ProductDetails to perform subscription.

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However, our legacy code haven't adopted ProductDetails. We are still using legacy SkuDetails

I was wondering, is it OK for us to

1. Add a completely new subscription plan for the yearly plan.
2. Continue to use legacy SkuDetails to perform subscription.

Is there any shortcoming, or pitfall for doing so?

Thanks.