Why would the spread remain almost the same?

I have read some of the internet postings regarding possible voting machine fraud in the Obama/Clinton NH race for which I have not reached a conclusion.  However, I did notice an almost equal spread between their vote counts throughout the evening.  Having followed live voting results since the Kennedy/Nixon race in 1960, I am used to witnessing a sea-saw change between the candidates as various precincts which are strong for one candidate or the other randomly report their results. In contrast, I never saw this usual pattern, but rather one of an almost equal spread throughout the night which could result from a programmed mathematical formula.

While I am strongly opposed to electronic voting, I have no evidence of outright fraud.  However, I do feel it rather noteworthy that the normally expected sea/saw pattern did not occur in this election.