Pivot table incorrectly summing & producing strange numbers (-2.66454E-15)

I have a pivot table generated by some vba code which previously has worked fine.

It is now incorrectly summing a numeric column containing figures to two decimal places. An extract of the report is here;

Smith, MD 862.83
Smith, MDP 147.17
Stiles, M J 132.06
Storrar, SJ 12
Thompson, A E -2.66454E-15
Thorp, N J 1
Watts, J 120.89
Webb, JH 10
Weston, L 8.25
Wichard, D L 2.5

The problem seems confined to three specific names but I can't see any differences here and this may just be coincidental.

Could anyone help with some advice please?

Thanks,

Steve

I think maybe your data has some very small numbers that appear as 0.00 because of cell formats.

are these financial data? I sometimes see these very small exponential numbers in data imported from finance systems where money in and money out are supposed to be balanced & self-cancelling but, probably because of some rounding error, aren't.