Custom Fields in Organization Table Not Saving Values

organization({
  schema: {
    organization: {
      modelName: "firestorm_organizations",
      fields: {
        createdAt: "created_at",
      },
      additionalFields: {
        company_size: {
          type: "string",
          required: false,
          defaultValue: null,
        },
        stripe_customer_id: {
          type: "string",
          required: false,
          defaultValue: null,
        },
      },
    },
    // other schema configs...
  },
  // other config...
})

const organization = await auth.api.createOrganization({
  request: req,
  headers: req.headers,
  body: {
    name: body.companyName,
    slug: "",
    company_size: body.companySize, // This value isn't being saved
  },
})

ALTER TABLE firestorm_organizations ADD COLUMN company_size TEXT;