Spec issue with pointless occurrences of <sequence>, <choice> or <all>

> Schema Component Constraint: Particle Valid (Restriction) 
> ...
> 2.2 Any pointless occurrences of <sequence> <l >, <choice> <l > or
> <all> <l > are ignored
> 
> Application of this rule will make following schema invalid. Is that
> desired behavior?
> 
> <xs:schema elementFormDefault="qualified" targetNamespace=""
> xmlns:xs="http://www.w3.org/2001/XMLSchema">
>     <xs:complexType name="base">
>         <xs:sequence>
>             <xs:sequence maxOccurs="2">
>                 <xs:element name="a"/>
>                 <xs:element name="b"/>
>             </xs:sequence>
>             <xs:sequence maxOccurs="2">
>                 <xs:element name="a"/>
>                 <xs:element name="b"/>
>             </xs:sequence>
>         </xs:sequence>
>     </xs:complexType>
>     <xs:complexType name="derived">
>         <xs:complexContent>
>             <xs:restriction base="base">
>                 <xs:sequence>
>                     <xs:sequence maxOccurs="1">
>                         <xs:element name="a"/>
>                         <xs:element name="b"/>
>                     </xs:sequence>
>                     <xs:sequence maxOccurs="1">
>                         <xs:element name="a"/>
>                         <xs:element name="b"/>
>                     </xs:sequence>
>                 </xs:sequence>
>             </xs:restriction>
>         </xs:complexContent>
>     </xs:complexType>
> </xs:schema>
> 
> Thanks, Yan
>