just for the future 5525k wood = 5.525.000 wood. k is short for kilo. the prefix kilo means thousand. for example: 1kg is 1 KiloGram where as 1g is 1 Gram. and 1 kilogram = 1000 grams. k means thousand.
if the scenario you are trying to prevent is the accidental training of the wrong type of troop, a confirmation box (which could be toggled off) that prompts you if you meant to train this type of troop would be a better fix than transferring resources into a second troop type.
you also left out the details about what should happen if there is extra resources remaining from the conversion? do you lose them? are they added to your village again?