Even the lower limit of that differential compounds to a hefty sum over time.
( Even ( ( ( the ( lower limit ) ) ( of ( that differential ) ) ) ( ( compounds ( to ( ( a ( hefty sum ) ) ( over time ) ) ) ) . ) ) )
(ROOT (S (ADVP (RB Even)) (NP (NP (DT the) (JJR lower) (NN limit)) (PP (IN of) (NP (DT that) (NN differential)))) (VP (VBZ compounds) (PP (TO to) (NP (NP (DT a) (JJ hefty) (NN sum)) (PP (IN over) (NP (NN time)))))) (. .)))
The differential doubles every month.
( ( The differential ) ( ( doubles ( every month ) ) . ) )
(ROOT (S (NP (DT The) (NN differential)) (VP (VBZ doubles) (NP (DT every) (NN month))) (. .)))