Schedules two notes alongside central thematic element (7)

'schedules' is the definition.
Although both the answer and definition are plural nouns, I cannot understand how one could define the other.

'two notes alongside central thematic element' is the wordplay.
'two notes' can mean two replacements for 'note'.
'note' becomes 'ti' (musical note, as in do re mi so fa la ti do).
'note' becomes 'mi' (as in do-re-mi).
'alongside central thematic element' becomes 'ngs' (I can't justify this - if you can you should give a lot more credence to this answer).
'ti'+'mi'+'ngs'='TIMINGS'

Can you help me to learn more?