"in one sum" is correct and can be used in written English.
It is usually used to refer to the total amount of money that is due. For example, "I paid the dues for the entire year in one sum."
Taking the full 25% tax-free lump sum in one go "crystallises" the pension.
Two different decomposition methods, leading to one sum in real space and one in reciprocal space, are considered.
(a) Whenever feasible, the General Services Administration GSAA) will collect the total amount of a debt in one lump sum.
Group field theories provide one of the most promising framework for a background-free theory of quantum gravity in which one sums both over topologies and geometries.
I should point out that the fact that it was being paid tax free and in one lump sum did not impact the amount paid.
But IUDs are also the most expensive method, costing between $500 and $1,000 in one lump sum.
Admitted students will have the option of paying their tuition in three payments (40%, 30 %, 30) or in one lump sum.
The prince had told Christie's that he intended to pay in one lump sum upon completion of the sale.
Ask yourself, if you take it in one lump sum what would you use the money for?
The fees to the surrogate would be paid out in monthly installments, not in one lump sum at the end.
