And the silver of them that were numbered (פְּקוּדֵ֥י) of the congregation was an hundred talents, and a thousand seven hundred and threescore and fifteen shekels, after the shekel of the sanctuary (Exodus 38:25 KJV)
The word פָּקַד is most often translated as numbered. But that is just one of the meanings of this word. It can mean visit, punish, appoint, commit, miss, set, charge, governor, lack, oversight, officers, empty, ruler, overseer, judgment, and other. [H6485-paqad] For example the exact word is used where it does not mean numbered, or counted as in a census:
And Moses was wroth with the officers (פְּקוּדֵ֣י) of the host, with the captains over thousands, and captains over hundreds, which came from the battle. (Numbers 31:4 KJV)
While a formal census had not yet been taken, there is an earlier event in which Moses selected a group and appointed them to resolve disputes:
And Moses chose able men out of all Israel, and made them heads over the people, rulers of thousands, rulers of hundreds, rulers of fifties, and rulers of tens. And they judged the people at all seasons: the hard causes they brought unto Moses, but every small matter they judged themselves. (Exodus 18:25-26 KJV)
Moses appointed individuals to resolve disputes over groups of thousands, hundreds, fifties, and tens. Similar to a census, this requires counting the people. The difference is the focus is making smaller groups for the purpose of assigning a ruler. Whereas a census is focused in the opposite direction: building up from smaller groups to arrive at at total. In other words, to assign a ruler of a group of 1,000, you take 1,000 away from the total, without regard for the total.
Also, unlike a census to determine the total number, the text in Exodus 18 is not clear. Are the larger groups made from smaller groups? Or are the smaller groups made from the rulers of the larger groups? If Moses' system of dispute resolution is viewed from the "bottom up" an issue too difficult for the ruler of ten would go to the ruler of fifty, and so forth. If viewed from the "top down" where the difficult issues went directly to Moses, then the people were first put into groups of 1,000. Then the rulers of thousands were put into groups of hundreds. Then the rulers of hundreds were put into groups of fifties. Lastly the rulers of fifties were put into groups of ten. I believe the latter is more in line with the text. Each individual had a single judge who took the matter directly to Moses if it was too difficult.
There is also the consideration of children. No explanation is given as to how old a person was in order to be placed in a group but it is unlikely the rules for a census would be used. More reasonable would be to use the age of accountability. Disputes were resolved by parents until the child reached the age of accountability after which the individual went into a group and their disputes were no longer treated as a family matter.
Regardless of how the people were assigned to a group or how old they were to be included, the "conflict" can be resolved by understanding the silver for the tabernacle was determined from the counting of the people for the purpose of appointing judges to resolve disputes:
And the silver of them that were appointed or counted of the congregation [cf Exodus 18:25-26] was an hundred talents, and a thousand seven hundred and threescore and fifteen shekels, after the shekel of the sanctuary