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It's not clear what you are doing about component tolerances. You can get 218 pF with a 150 pF and a 68 pF in parallel. That is just within +1% of 216 pF. A single 220 pF is within +2%. If all your four capacitors have +/-1% tolerance, your 216 pF will also have +/-1% tolerance, but there are many additional stray capacitances with this arrangement. Fewer capacitors, fewer strays and simpler construction.

What you're saying about tolerance is only half-true. Paralleling multiple capacitances doesn't change the worst cases. But it does change the standard deviation. Assuming 4 equal valued capacitors in parallel reduces σ by √4. If the nominal values of the capacitors are not equal the situation is much more complicated.

In general, it is a much better idea, when trying to obtain a non-standard value, to get as close as you can with one high tolerance capacitor and add a much smaller one in parallel that can be a much looser tolerance. You can get 218p with 200p and 18p. You only need to specify the 200p as a 1%. The 18p could be a 10% for the same effect on overall tolerance.

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Regards,
Tony