has to be used for in how many days vs has to be used for how many days

Some examples from the web:

• There's no rule that says it has to be used for drinking.
• It has to be used for the prophylaxis of influenza in an officially declared pandemic situation.
• A more practical definition of SMEs has to be used for the work of the Forum.
• The same principle that goes for international co-operation has to be used for cross-border and interregional co-operation.
• The same principle that goes for international co-operation has to be used for cross-border and interregional co-operation.
• The same principle that goes for international co-operation has to be used for cross-border and interregional co-operation.
• For complete air-conditioning systems the actual nominal charge has to be used.
• The KwikPen has to be used as recommended in the user manual.
• The description has to be used to select the code for a specific situation.
• The most wood has to be used in dwelling houses.
• It recognises that current infrastructure has to be used optimally partly by improving the efficiency of transhipment.
• It has to be used discreetly and effectively if it is to bring results.
• In order to verify this compatibility the procedure specified in annex 5D has to be used.
• Generally the arrangement with six microphone positions on a hemispherical measurement surface has to be used.
• The former has to be used purely as a supplementary criterion.
• Each item has to be used at a specific time and place to accomplish whatever I needed to get done.
• The intravenous route has to be used (please see section 4.4 - chronic renal failure patients).
• OptiSet has to be used as recommended in these Instructions for Use (see section 6.6).
• At the end of this period the product has to be used or discarded.
• The handling of the Kurdish issue also has to be used as a criterion for assessing the reform process.

Some examples from the web:

• There's no rule that says it has to be used for drinking.
• It has to be used for the prophylaxis of influenza in an officially declared pandemic situation.
• A more practical definition of SMEs has to be used for the work of the Forum.
• The Russian authorities are constructing stands, intended to be used for only 14 days during the Olympics, on the location of the oldest part of the village.
• 8. Store at -20 ºC or below. If to be used after day of opening, add 0,1 ml of a solution containing 100 gram sodium azide per litre.
• The same principle that goes for international co-operation has to be used for cross-border and interregional co-operation.
• The same principle that goes for international co-operation has to be used for cross-border and interregional co-operation.
• The same principle that goes for international co-operation has to be used for cross-border and interregional co-operation.
• I'm giving you these drops, to be used once a day for the rest of your life.
• This should only be used for a few days.
• After the last day of treatment with Pirsue, milk from treated cows should not be used for 5 days.
• It is recommended that a dose of 37.5 mg/ day of prolonged-release venlafaxine be used for 7 days.
• After the last administration of Novem to cattle, the milk should not be used for 5 days.
• We find it difficult to insist for all eternity that a certain product can only be used for eight days.
• For complete air-conditioning systems the actual nominal charge has to be used.
• The KwikPen has to be used as recommended in the user manual.
• The description has to be used to select the code for a specific situation.
• The most wood has to be used in dwelling houses.
• It recognises that current infrastructure has to be used optimally partly by improving the efficiency of transhipment.
• It has to be used discreetly and effectively if it is to bring results.