Full Idea
In the new tenseless theory, no tensed token sentence can be equivalent to a tenseless token, because the former, unlike the latter, draws attention to the context in which it is tokened.
Gist of Idea
Actual tensed sentences cannot be tenseless, because they can cite their own context
Source
report of John Perry (The Problem of the Essential Indexical [1979]) by Robin Le Poidevin - Past, Present and Future of Debate about Tense 3 a
Book Reference
'Questions of Time and Tense', ed/tr. Le Poidevin,R [OUP 2002], p.29
A Reaction
So the problem about indexicals was worrying fans of the tenseless B-series view of time (and so it should). I'm inclined to translate sentences containing indexicals into their actual propositions, which tend to avoid them. 'Time/person of utterance'.