Actually, a similar trend occurs in Ro→De (Table 8), but with a relatively higher error reduction in case of the Transformer model.
the Transformer model shows reductions of −2.29 points for ZST A and −4.53 for ZST B, whereas for the Recurrent model the improvements are slightly lower, namely −1.11 (ZST A) and −4.14 (ZST B) points.