Fix deltaFactor for old webkits

When delta is more than or equal to `120` - we devide it by `40` to get delta in pixels.
If we check only for delta being equal to `120` we get `deltaFactor` equal to `240` sometimes.
https://www.monosnap.com/file/OXQ113pLoDnYCFDbiQDhZO0ceKXzfE