We could say their meanings are similar (iterated activity), but at what stratum? A stratified account allows for the proportions you have observed, without having to undo rank as the entry point for grammatical systems.
 In SFL theory, linguistic meaning is modelled at the level of semantics. Here Rose follows Martin (1992: 21, 40, 55, 56, 96, 137) in confusing semogenesis ("all strata make meaning") with stratification (meaning–wording–sounding). See, for example, the clarifying critiques here, here, here, here or here.
 In SFL theory, strata represent different levels along the dimension of symbolic abstraction. Here Rose's notion of what constitutes a "stratified account" follows Martin (1992: 129, 390, 391, 392, 488, 490-1) in misconstruing strata as "interacting modules" of meaning, to which theoretical categories can be allocated, without regard for the level of symbolic abstraction. See, for example, the clarifying critiques here, here, here or here. Halliday & Webster (2009: 231):
In SFL language is described, or “modelled”, in terms of several dimensions, or parameters, which taken together define the “architecture” of language. These are
- (i) the hierarchy of strata (context, semantics, lexicogrammar, phonology, phonetics; related by realisation);
- (ii) the hierarchy of rank (e.g. clause, phrase/group, word, morpheme; related by composition);
- (iii) the cline of instantiation (system to instance);
- (iv) the cline of delicacy (least delicate to most delicate, or grossest to finest);
- (v) the opposition of axis (paradigmatic and syntagmatic);
- (vi) the organisation by metafunction (ideational (experiential, logical), interpersonal, textual).